diff --git a/market-contract/Cargo.lock b/market-contract/Cargo.lock
index b7302d4..eea0860 100644
--- a/market-contract/Cargo.lock
+++ b/market-contract/Cargo.lock
@@ -10,18 +10,32 @@ checksum = "fe438c63458706e03479442743baae6c88256498e6431708f6dfc520a26515d3"
 
 [[package]]
 name = "ahash"
-version = "0.4.7"
+version = "0.7.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "739f4a8db6605981345c5654f3a85b056ce52f37a39d34da03f25bf2151ea16e"
+checksum = "fcb51a0695d8f838b1ee009b3fbf66bda078cd64590202a864a8f3e8c4315c47"
+dependencies = [
+ "getrandom 0.2.7",
+ "once_cell",
+ "version_check",
+]
 
 [[package]]
-name = "aho-corasick"
-version = "0.7.15"
+name = "arrayref"
+version = "0.3.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7404febffaa47dac81aa44dba71523c9d069b1bdc50a77db41195149e17f68e5"
-dependencies = [
- "memchr",
-]
+checksum = "a4c527152e37cf757a3f78aae5a06fbeefdb07ccc535c980a3208ee3060dd544"
+
+[[package]]
+name = "arrayvec"
+version = "0.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "23b62fc65de8e4e7f52534fb52b0f3ed04746ae267519eef2a83941e8085068b"
+
+[[package]]
+name = "arrayvec"
+version = "0.7.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8da52d66c7071e2e3fa2a1e5c6d088fec47b593032b254f5e980de8ea54454d6"
 
 [[package]]
 name = "autocfg"
@@ -29,12 +43,41 @@ version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cdb031dd78e28731d87d56cc8ffef4a8f36ca26c38fe2de700543e627f8a464a"
 
+[[package]]
+name = "base64"
+version = "0.11.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b41b7ea54a0c9d92199de89e20e58d49f02f8e699814ef3fdf266f6f748d15c7"
+
 [[package]]
 name = "base64"
 version = "0.13.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "904dfeac50f3cdaba28fc6f57fdcddb75f49ed61346676a78c4ffe55877802fd"
 
+[[package]]
+name = "bitvec"
+version = "0.20.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7774144344a4faa177370406a7ff5f1da24303817368584c6206c8303eb07848"
+dependencies = [
+ "funty",
+ "radium",
+ "tap",
+ "wyz",
+]
+
+[[package]]
+name = "blake2"
+version = "0.9.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0a4e37d16930f5459780f5621038b6382b9bb37c19016f39fb6b5808d831f174"
+dependencies = [
+ "crypto-mac",
+ "digest 0.9.0",
+ "opaque-debug",
+]
+
 [[package]]
 name = "block-buffer"
 version = "0.9.0"
@@ -45,6 +88,15 @@ dependencies = [
  "generic-array",
 ]
 
+[[package]]
+name = "block-buffer"
+version = "0.10.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0bf7fe51849ea569fd452f37822f606a5cabb684dc918707a0193fd4664ff324"
+dependencies = [
+ "generic-array",
+]
+
 [[package]]
 name = "block-padding"
 version = "0.2.1"
@@ -53,9 +105,9 @@ checksum = "8d696c370c750c948ada61c69a0ee2cbbb9c50b1019ddb86d9317157a99c2cae"
 
 [[package]]
 name = "borsh"
-version = "0.8.1"
+version = "0.9.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a5a26c53ddf60281f18e7a29b20db7ba3db82a9d81b9650bfaa02d646f50d364"
+checksum = "15bf3650200d8bffa99015595e10f1fbd17de07abbc25bb067da79e769939bfa"
 dependencies = [
  "borsh-derive",
  "hashbrown",
@@ -63,22 +115,22 @@ dependencies = [
 
 [[package]]
 name = "borsh-derive"
-version = "0.8.1"
+version = "0.9.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b637a47728b78a78cd7f4b85bf06d71ef4221840e059a38f048be2422bf673b2"
+checksum = "6441c552f230375d18e3cc377677914d2ca2b0d36e52129fe15450a2dce46775"
 dependencies = [
  "borsh-derive-internal",
  "borsh-schema-derive-internal",
- "proc-macro-crate",
+ "proc-macro-crate 0.1.5",
  "proc-macro2",
  "syn",
 ]
 
 [[package]]
 name = "borsh-derive-internal"
-version = "0.8.1"
+version = "0.9.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d813fa25eb0bed78c36492cff4415f38c760d6de833d255ba9095bd8ebb7d725"
+checksum = "5449c28a7b352f2d1e592a8a28bf139bc71afb0764a14f3c02500935d8c44065"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -87,9 +139,9 @@ dependencies = [
 
 [[package]]
 name = "borsh-schema-derive-internal"
-version = "0.8.1"
+version = "0.9.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dcf78ee4a98c8cb9eba1bac3d3e2a1ea3d7673c719ce691e67b5cbafc472d3b7"
+checksum = "cdbd5696d8bfa21d53d9fe39a714a18538bad11492a42d066dbbc395fb1951c0"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -102,12 +154,40 @@ version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "771fe0050b883fcc3ea2359b1a96bcfbc090b7116eae7c3c512c7a083fdf23d3"
 
+[[package]]
+name = "byte-slice-cast"
+version = "1.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "87c5fdd0166095e1d463fc6cc01aa8ce547ad77a4e84d42eb6762b084e28067e"
+
 [[package]]
 name = "byteorder"
 version = "1.4.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ae44d1a3d5a19df61dd0c8beb138458ac2a53a7ac09eba97d55592540004306b"
 
+[[package]]
+name = "bytesize"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6c58ec36aac5066d5ca17df51b3e70279f5670a72102f5752cb7e7c856adfc70"
+
+[[package]]
+name = "c2-chacha"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d27dae93fe7b1e0424dc57179ac396908c26b035a87234809f5c4dfd1b47dc80"
+dependencies = [
+ "cipher",
+ "ppv-lite86",
+]
+
+[[package]]
+name = "cc"
+version = "1.0.73"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2fff2a6927b3bb87f9595d67196a70493f627687a71d87a0d692242c33f58c11"
+
 [[package]]
 name = "cfg-if"
 version = "0.1.10"
@@ -120,12 +200,83 @@ version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
 
+[[package]]
+name = "chrono"
+version = "0.4.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "670ad68c9088c2a963aaa298cb369688cf3f9465ce5e2d4ca10e6e0098a1ce73"
+dependencies = [
+ "libc",
+ "num-integer",
+ "num-traits",
+ "serde",
+ "time",
+ "winapi",
+]
+
+[[package]]
+name = "cipher"
+version = "0.2.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "12f8e7987cbd042a63249497f41aed09f8e65add917ea6566effbc56578d6801"
+dependencies = [
+ "generic-array",
+]
+
+[[package]]
+name = "cpufeatures"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "59a6001667ab124aebae2a495118e11d30984c3a653e99d86d58971708cf5e4b"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "cpuid-bool"
 version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8aebca1129a03dc6dc2b127edd729435bbc4a37e1d5f4d7513165089ceb02634"
 
+[[package]]
+name = "crunchy"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7a81dae078cea95a014a339291cec439d2f232ebe854a9d672b796c6afafa9b7"
+
+[[package]]
+name = "crypto-common"
+version = "0.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "57952ca27b5e3606ff4dd79b0020231aaf9d6aa76dc05fd30137538c50bd3ce8"
+dependencies = [
+ "generic-array",
+ "typenum",
+]
+
+[[package]]
+name = "crypto-mac"
+version = "0.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b584a330336237c1eecd3e94266efb216c56ed91225d634cb2991c5f3fd1aeab"
+dependencies = [
+ "generic-array",
+ "subtle",
+]
+
+[[package]]
+name = "curve25519-dalek"
+version = "3.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "90f9d052967f590a76e62eb387bd0bbb1b000182c3cefe5364db6b7211651bc0"
+dependencies = [
+ "byteorder",
+ "digest 0.9.0",
+ "rand_core 0.5.1",
+ "subtle",
+ "zeroize",
+]
+
 [[package]]
 name = "derive_more"
 version = "0.99.11"
@@ -146,6 +297,63 @@ dependencies = [
  "generic-array",
 ]
 
+[[package]]
+name = "digest"
+version = "0.10.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f2fb860ca6fafa5552fb6d0e816a69c8e49f0908bf524e30a90d97c85892d506"
+dependencies = [
+ "block-buffer 0.10.2",
+ "crypto-common",
+]
+
+[[package]]
+name = "easy-ext"
+version = "0.2.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "53aff6fdc1b181225acdcb5b14c47106726fd8e486707315b1b138baed68ee31"
+
+[[package]]
+name = "ed25519"
+version = "1.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1e9c280362032ea4203659fc489832d0204ef09f247a0506f170dafcac08c369"
+dependencies = [
+ "signature",
+]
+
+[[package]]
+name = "ed25519-dalek"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c762bae6dcaf24c4c84667b8579785430908723d5c889f469d76a41d59cc7a9d"
+dependencies = [
+ "curve25519-dalek",
+ "ed25519",
+ "rand 0.7.3",
+ "serde",
+ "sha2 0.9.3",
+ "zeroize",
+]
+
+[[package]]
+name = "fixed-hash"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cfcf0ed7fe52a17a03854ec54a9f76d6d84508d1c0e66bc1793301c73fc8493c"
+dependencies = [
+ "byteorder",
+ "rand 0.8.5",
+ "rustc-hex",
+ "static_assertions",
+]
+
+[[package]]
+name = "funty"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fed34cd105917e91daa4da6b3728c47b068749d6a62c59811f06ed2ac71d9da7"
+
 [[package]]
 name = "generic-array"
 version = "0.14.4"
@@ -156,15 +364,43 @@ dependencies = [
  "version_check",
 ]
 
+[[package]]
+name = "getrandom"
+version = "0.1.16"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8fc3cb4d91f53b50155bdcfd23f6a4c39ae1969c2ae85982b135750cccaf5fce"
+dependencies = [
+ "cfg-if 1.0.0",
+ "libc",
+ "wasi 0.9.0+wasi-snapshot-preview1",
+]
+
+[[package]]
+name = "getrandom"
+version = "0.2.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4eb1a864a501629691edf6c15a593b7a51eebaa1e8468e9ddc623de7c9b58ec6"
+dependencies = [
+ "cfg-if 1.0.0",
+ "libc",
+ "wasi 0.11.0+wasi-snapshot-preview1",
+]
+
 [[package]]
 name = "hashbrown"
-version = "0.9.1"
+version = "0.11.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d7afe4a420e3fe79967a00898cc1f4db7c8a49a9333a29f8a4bd76a253d5cd04"
+checksum = "ab5ef0d4909ef3724cc8cce6ccc8572c5c817592e9285f5464f8e86f8bd3726e"
 dependencies = [
  "ahash",
 ]
 
+[[package]]
+name = "heck"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2540771e65fc8cb83cd6e8a237f70c319bd5c29f78ed1084ba5d50eeac86f7f9"
+
 [[package]]
 name = "hex"
 version = "0.4.2"
@@ -172,13 +408,23 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "644f9158b2f133fd50f5fb3242878846d9eb792e445c893805ff0e3824006e35"
 
 [[package]]
-name = "indexmap"
-version = "1.6.1"
+name = "impl-codec"
+version = "0.5.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4fb1fa934250de4de8aef298d81c729a7d33d8c239daa3a7575e6b92bfc7313b"
+checksum = "161ebdfec3c8e3b52bf61c4f3550a1eea4f9579d10dc1b936f3171ebdcd6c443"
 dependencies = [
- "autocfg",
- "hashbrown",
+ "parity-scale-codec",
+]
+
+[[package]]
+name = "impl-trait-for-tuples"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "11d7a9f6330b71fea57921c9b61c47ee6e84f72d394754eff6163ae67e7395eb"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
 ]
 
 [[package]]
@@ -194,93 +440,133 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "67c21572b4949434e4fc1e1978b99c5f77064153c59d998bf13ecd96fb5ecba7"
 
 [[package]]
-name = "lazy_static"
-version = "1.4.0"
+name = "libc"
+version = "0.2.126"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
+checksum = "349d5a591cd28b49e1d1037471617a32ddcda5731b99419008085f72d5a53836"
 
 [[package]]
-name = "libc"
-version = "0.2.86"
+name = "memory_units"
+version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b7282d924be3275cec7f6756ff4121987bc6481325397dde6ba3e7802b1a8b1c"
+checksum = "8452105ba047068f40ff7093dd1d9da90898e63dd61736462e9cdda6a90ad3c3"
 
 [[package]]
-name = "memchr"
-version = "2.3.4"
+name = "near-account-id"
+version = "0.13.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0ee1c47aaa256ecabcaea351eae4a9b01ef39ed810004e298d2511ed284b1525"
+checksum = "de83d74a9241be8cc4eb3055216966b58bf8c463e8e285c0dc553925acdd19fa"
+dependencies = [
+ "borsh",
+ "serde",
+]
 
 [[package]]
-name = "memory_units"
-version = "0.4.0"
+name = "near-crypto"
+version = "0.13.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8452105ba047068f40ff7093dd1d9da90898e63dd61736462e9cdda6a90ad3c3"
+checksum = "b8ecf0b8b31aa7f4e60f629f72213a2617ca4a5f45cd1ae9ed2cf7cecfebdbb7"
+dependencies = [
+ "arrayref",
+ "blake2",
+ "borsh",
+ "bs58",
+ "c2-chacha",
+ "curve25519-dalek",
+ "derive_more",
+ "ed25519-dalek",
+ "libc",
+ "near-account-id",
+ "once_cell",
+ "parity-secp256k1",
+ "primitive-types",
+ "rand 0.7.3",
+ "rand_core 0.5.1",
+ "serde",
+ "serde_json",
+ "subtle",
+ "thiserror",
+]
 
 [[package]]
-name = "near-primitives-core"
-version = "0.4.0"
+name = "near-primitives"
+version = "0.13.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c2b3fb5acf3a494aed4e848446ef2d6ebb47dbe91c681105d4d1786c2ee63e52"
+checksum = "0a2ba19282e79a4485a77736b679d276b09870bbf8042a18e0f0ae36347489c5"
 dependencies = [
- "base64",
  "borsh",
- "bs58",
+ "byteorder",
+ "bytesize",
+ "chrono",
  "derive_more",
+ "easy-ext",
  "hex",
- "lazy_static",
+ "near-crypto",
+ "near-primitives-core",
+ "near-rpc-error-macro",
+ "near-vm-errors",
  "num-rational",
+ "once_cell",
+ "primitive-types",
+ "rand 0.7.3",
+ "reed-solomon-erasure",
  "serde",
  "serde_json",
- "sha2",
+ "smart-default",
+ "strum",
+ "thiserror",
 ]
 
 [[package]]
-name = "near-rpc-error-core"
-version = "0.1.0"
+name = "near-primitives-core"
+version = "0.13.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ffa8dbf8437a28ac40fcb85859ab0d0b8385013935b000c7a51ae79631dd74d9"
+checksum = "bb561feb392bb8c4f540256073446e6689af087bf6356e8dddcf75fc279f201f"
 dependencies = [
- "proc-macro2",
- "quote",
+ "base64 0.11.0",
+ "borsh",
+ "bs58",
+ "derive_more",
+ "near-account-id",
+ "num-rational",
  "serde",
- "serde_json",
- "syn",
+ "sha2 0.10.2",
+ "strum",
 ]
 
 [[package]]
-name = "near-rpc-error-macro"
-version = "0.1.0"
+name = "near-rpc-error-core"
+version = "0.13.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0c6111d713e90c7c551dee937f4a06cb9ea2672243455a4454cc7566387ba2d9"
+checksum = "77fdd7ea8d8f786878651c37691515d5053f827ae60894aa40c16882b78f77c9"
 dependencies = [
- "near-rpc-error-core",
- "proc-macro2",
  "quote",
  "serde",
- "serde_json",
  "syn",
 ]
 
 [[package]]
-name = "near-runtime-utils"
-version = "4.0.0-pre.1"
+name = "near-rpc-error-macro"
+version = "0.13.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a48d80c4ca1d4cf99bc16490e1e3d49826c150dfc4410ac498918e45c7d98e07"
+checksum = "e521842b6ae864dfe5391afbbe2df9e9d8427c26e9333b2e0b65cd42094f7607"
 dependencies = [
- "lazy_static",
- "regex",
+ "near-rpc-error-core",
+ "serde",
+ "syn",
 ]
 
 [[package]]
 name = "near-sdk"
-version = "4.0.0-pre.4"
+version = "4.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "10f570e260eae9169dd5ffe0764728b872c2df79b8786dfb5e57183bd383908e"
+checksum = "bda34e06e28fb9a09ac54efbdc49f0c9308780fc932aaa81c49c493fde974045"
 dependencies = [
- "base64",
+ "base64 0.13.0",
  "borsh",
  "bs58",
+ "near-crypto",
+ "near-primitives",
  "near-primitives-core",
  "near-sdk-macros",
  "near-sys",
@@ -292,9 +578,9 @@ dependencies = [
 
 [[package]]
 name = "near-sdk-macros"
-version = "4.0.0-pre.4"
+version = "4.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "65ddca18086f1ab14ce8541e0c23f503a322d45914f2fe08f571844045d32bde"
+checksum = "72064fcc15a623a0d40a6c199ea5cbdc30a83cae4816889d46f218acf31bfba8"
 dependencies = [
  "Inflector",
  "proc-macro2",
@@ -304,37 +590,40 @@ dependencies = [
 
 [[package]]
 name = "near-sys"
-version = "0.1.0"
+version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f6a7aa3f46fac44416d8a93d14f30a562c4d730a1c6bf14bffafab5f475c244a"
+checksum = "e307313276eaeced2ca95740b5639e1f3125b7c97f0a1151809d105f1aa8c6d3"
 
 [[package]]
 name = "near-vm-errors"
-version = "4.0.0-pre.1"
+version = "0.13.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e281d8730ed8cb0e3e69fb689acee6b93cdb43824cd69a8ffd7e1bfcbd1177d7"
+checksum = "0e02faf2bc1f6ef82b965cfe44389808fb5594f7aca4b596766117f4ce74df20"
 dependencies = [
  "borsh",
- "hex",
+ "near-account-id",
  "near-rpc-error-macro",
  "serde",
 ]
 
 [[package]]
 name = "near-vm-logic"
-version = "4.0.0-pre.1"
+version = "0.13.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e11cb28a2d07f37680efdaf860f4c9802828c44fc50c08009e7884de75d982c5"
+checksum = "f024d90451cd3c24d7a0a5cabf3636b192a60eb8e3ff0456f6c18b91152c346d"
 dependencies = [
- "base64",
+ "base64 0.13.0",
  "borsh",
  "bs58",
  "byteorder",
+ "near-account-id",
+ "near-crypto",
+ "near-primitives",
  "near-primitives-core",
- "near-runtime-utils",
  "near-vm-errors",
+ "ripemd",
  "serde",
- "sha2",
+ "sha2 0.9.3",
  "sha3",
 ]
 
@@ -390,9 +679,9 @@ dependencies = [
 
 [[package]]
 name = "once_cell"
-version = "1.5.2"
+version = "1.12.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "13bd41f508810a131401606d54ac32a467c97172d74ba7662562ebba5ad07fa0"
+checksum = "7709cef83f0c1f58f666e746a08b21e0085f7440fa6a29cc194d68aac97a4225"
 
 [[package]]
 name = "opaque-debug"
@@ -400,6 +689,61 @@ version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "624a8340c38c1b80fd549087862da4ba43e08858af025b236e509b6649fc13d5"
 
+[[package]]
+name = "parity-scale-codec"
+version = "2.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "373b1a4c1338d9cd3d1fa53b3a11bdab5ab6bd80a20f7f7becd76953ae2be909"
+dependencies = [
+ "arrayvec 0.7.2",
+ "bitvec",
+ "byte-slice-cast",
+ "impl-trait-for-tuples",
+ "parity-scale-codec-derive",
+ "serde",
+]
+
+[[package]]
+name = "parity-scale-codec-derive"
+version = "2.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1557010476e0595c9b568d16dcfb81b93cdeb157612726f5170d31aa707bed27"
+dependencies = [
+ "proc-macro-crate 1.1.3",
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "parity-secp256k1"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4fca4f82fccae37e8bbdaeb949a4a218a1bbc485d11598f193d2a908042e5fc1"
+dependencies = [
+ "arrayvec 0.5.2",
+ "cc",
+ "cfg-if 0.1.10",
+ "rand 0.7.3",
+]
+
+[[package]]
+name = "ppv-lite86"
+version = "0.2.16"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "eb9f9e6e233e5c4a35559a617bf40a4ec447db2e84c20b55a6f83167b7e57872"
+
+[[package]]
+name = "primitive-types"
+version = "0.10.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "05e4722c697a58a99d5d06a08c30821d7c082a4632198de1eaa5a6c22ef42373"
+dependencies = [
+ "fixed-hash",
+ "impl-codec",
+ "uint",
+]
+
 [[package]]
 name = "proc-macro-crate"
 version = "0.1.5"
@@ -409,6 +753,16 @@ dependencies = [
  "toml",
 ]
 
+[[package]]
+name = "proc-macro-crate"
+version = "1.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e17d47ce914bf4de440332250b0edd23ce48c005f59fab39d3335866b114f11a"
+dependencies = [
+ "thiserror",
+ "toml",
+]
+
 [[package]]
 name = "proc-macro2"
 version = "1.0.24"
@@ -428,22 +782,111 @@ dependencies = [
 ]
 
 [[package]]
-name = "regex"
-version = "1.4.3"
+name = "radium"
+version = "0.6.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d9251239e129e16308e70d853559389de218ac275b515068abc96829d05b948a"
+checksum = "643f8f41a8ebc4c5dc4515c82bb8abd397b527fc20fd681b7c011c2aee5d44fb"
+
+[[package]]
+name = "rand"
+version = "0.7.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6a6b1679d49b24bbfe0c803429aa1874472f50d9b363131f0e89fc356b544d03"
+dependencies = [
+ "getrandom 0.1.16",
+ "libc",
+ "rand_chacha 0.2.2",
+ "rand_core 0.5.1",
+ "rand_hc",
+]
+
+[[package]]
+name = "rand"
+version = "0.8.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "34af8d1a0e25924bc5b7c43c079c942339d8f0a8b57c39049bef581b46327404"
+dependencies = [
+ "libc",
+ "rand_chacha 0.3.1",
+ "rand_core 0.6.3",
+]
+
+[[package]]
+name = "rand_chacha"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f4c8ed856279c9737206bf725bf36935d8666ead7aa69b52be55af369d193402"
 dependencies = [
- "aho-corasick",
- "memchr",
- "regex-syntax",
- "thread_local",
+ "ppv-lite86",
+ "rand_core 0.5.1",
 ]
 
 [[package]]
-name = "regex-syntax"
-version = "0.6.22"
+name = "rand_chacha"
+version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b5eb417147ba9860a96cfe72a0b93bf88fee1744b5636ec99ab20c1aa9376581"
+checksum = "e6c10a63a0fa32252be49d21e7709d4d4baf8d231c2dbce1eaa8141b9b127d88"
+dependencies = [
+ "ppv-lite86",
+ "rand_core 0.6.3",
+]
+
+[[package]]
+name = "rand_core"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "90bde5296fc891b0cef12a6d03ddccc162ce7b2aff54160af9338f8d40df6d19"
+dependencies = [
+ "getrandom 0.1.16",
+]
+
+[[package]]
+name = "rand_core"
+version = "0.6.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d34f1408f55294453790c48b2f1ebbb1c5b4b7563eb1f418bcfcfdbb06ebb4e7"
+dependencies = [
+ "getrandom 0.2.7",
+]
+
+[[package]]
+name = "rand_hc"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ca3129af7b92a17112d59ad498c6f81eaf463253766b90396d39ea7a39d6613c"
+dependencies = [
+ "rand_core 0.5.1",
+]
+
+[[package]]
+name = "reed-solomon-erasure"
+version = "4.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a415a013dd7c5d4221382329a5a3482566da675737494935cbbbcdec04662f9d"
+dependencies = [
+ "smallvec",
+]
+
+[[package]]
+name = "ripemd"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1facec54cb5e0dc08553501fa740091086d0259ad0067e0d4103448e4cb22ed3"
+dependencies = [
+ "digest 0.10.3",
+]
+
+[[package]]
+name = "rustc-hex"
+version = "2.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3e75f6a532d0fd9f7f13144f392b6ad56a32696bfcd9c78f797f16bbb6f072d6"
+
+[[package]]
+name = "rustversion"
+version = "1.0.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f2cc38e8fa666e2de3c4aba7edeb5ffc5246c1c2ed0e3d17e560aeeba736b23f"
 
 [[package]]
 name = "ryu"
@@ -477,7 +920,6 @@ version = "1.0.62"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ea1c6153794552ea7cf7cf63b1231a25de00ec90db326ba6264440fa08e31486"
 dependencies = [
- "indexmap",
  "itoa",
  "ryu",
  "serde",
@@ -489,25 +931,93 @@ version = "0.9.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fa827a14b29ab7f44778d14a88d3cb76e949c45083f7dbfa507d0cb699dc12de"
 dependencies = [
- "block-buffer",
+ "block-buffer 0.9.0",
  "cfg-if 1.0.0",
  "cpuid-bool",
- "digest",
+ "digest 0.9.0",
  "opaque-debug",
 ]
 
+[[package]]
+name = "sha2"
+version = "0.10.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "55deaec60f81eefe3cce0dc50bda92d6d8e88f2a27df7c5033b42afeb1ed2676"
+dependencies = [
+ "cfg-if 1.0.0",
+ "cpufeatures",
+ "digest 0.10.3",
+]
+
 [[package]]
 name = "sha3"
 version = "0.9.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f81199417d4e5de3f04b1e871023acea7389672c4135918f05aa9cbf2f2fa809"
 dependencies = [
- "block-buffer",
- "digest",
+ "block-buffer 0.9.0",
+ "digest 0.9.0",
  "keccak",
  "opaque-debug",
 ]
 
+[[package]]
+name = "signature"
+version = "1.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f054c6c1a6e95179d6f23ed974060dcefb2d9388bb7256900badad682c499de4"
+
+[[package]]
+name = "smallvec"
+version = "1.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f2dd574626839106c320a323308629dcb1acfc96e32a8cba364ddc61ac23ee83"
+
+[[package]]
+name = "smart-default"
+version = "0.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "133659a15339456eeeb07572eb02a91c91e9815e9cbc89566944d2c8d3efdbf6"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "static_assertions"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a2eb9349b6444b326872e140eb1cf5e7c522154d69e7a0ffb0fb81c06b37543f"
+
+[[package]]
+name = "strum"
+version = "0.24.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "063e6045c0e62079840579a7e47a355ae92f60eb74daaf156fb1e84ba164e63f"
+dependencies = [
+ "strum_macros",
+]
+
+[[package]]
+name = "strum_macros"
+version = "0.24.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6878079b17446e4d3eba6192bb0a2950d5b14f0ed8424b852310e5a94345d0ef"
+dependencies = [
+ "heck",
+ "proc-macro2",
+ "quote",
+ "rustversion",
+ "syn",
+]
+
+[[package]]
+name = "subtle"
+version = "2.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6bdef32e8150c2a081110b42772ffe7d7c9032b606bc226c8260fd97e0976601"
+
 [[package]]
 name = "syn"
 version = "1.0.57"
@@ -520,12 +1030,52 @@ dependencies = [
 ]
 
 [[package]]
-name = "thread_local"
-version = "1.1.3"
+name = "synstructure"
+version = "0.12.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8018d24e04c95ac8790716a5987d0fec4f8b27249ffa0f7d33f1369bdfb88cbd"
+checksum = "f36bdaa60a83aca3921b5259d5400cbf5e90fc51931376a9bd4a0eb79aa7210f"
 dependencies = [
- "once_cell",
+ "proc-macro2",
+ "quote",
+ "syn",
+ "unicode-xid",
+]
+
+[[package]]
+name = "tap"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "55937e1799185b12863d447f42597ed69d9928686b8d88a1df17376a097d8369"
+
+[[package]]
+name = "thiserror"
+version = "1.0.31"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bd829fe32373d27f76265620b5309d0340cb8550f523c1dda251d6298069069a"
+dependencies = [
+ "thiserror-impl",
+]
+
+[[package]]
+name = "thiserror-impl"
+version = "1.0.31"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0396bc89e626244658bef819e22d0cc459e795a5ebe878e6ec336d1674a8d79a"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "time"
+version = "0.1.44"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6db9e6914ab8b1ae1c260a4ae7a49b6c5611b40328a735b21862567685e73255"
+dependencies = [
+ "libc",
+ "wasi 0.10.0+wasi-snapshot-preview1",
+ "winapi",
 ]
 
 [[package]]
@@ -539,9 +1089,21 @@ dependencies = [
 
 [[package]]
 name = "typenum"
-version = "1.12.0"
+version = "1.15.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "373c8a200f9e67a0c95e62a4f52fbf80c23b4381c05a17845531982fa99e6b33"
+checksum = "dcf81ac59edc17cc8697ff311e8f5ef2d99fcbd9817b34cec66f90b6c3dfd987"
+
+[[package]]
+name = "uint"
+version = "0.9.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "12f03af7ccf01dd611cc450a0d10dbc9b745770d096473e2faf0ca6e2d66d1e0"
+dependencies = [
+ "byteorder",
+ "crunchy",
+ "hex",
+ "static_assertions",
+]
 
 [[package]]
 name = "unicode-xid"
@@ -555,6 +1117,24 @@ version = "0.9.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b5a972e5669d67ba988ce3dc826706fb0a8b01471c088cb0b6110b805cc36aed"
 
+[[package]]
+name = "wasi"
+version = "0.9.0+wasi-snapshot-preview1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cccddf32554fecc6acb585f82a32a72e28b48f8c4c1883ddfeeeaa96f7d8e519"
+
+[[package]]
+name = "wasi"
+version = "0.10.0+wasi-snapshot-preview1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1a143597ca7c7793eff794def352d41792a93c481eb1042423ff7ff72ba2c31f"
+
+[[package]]
+name = "wasi"
+version = "0.11.0+wasi-snapshot-preview1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9c8d87e72b64a3b4db28d11ce29237c246188f4f51057d65a7eab63b7987e423"
+
 [[package]]
 name = "wee_alloc"
 version = "0.4.5"
@@ -588,3 +1168,30 @@ name = "winapi-x86_64-pc-windows-gnu"
 version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
+
+[[package]]
+name = "wyz"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "85e60b0d1b5f99db2556934e21937020776a5d31520bf169e851ac44e6420214"
+
+[[package]]
+name = "zeroize"
+version = "1.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4756f7db3f7b5574938c3eb1c117038b8e07f95ee6718c0efad4ac21508f1efd"
+dependencies = [
+ "zeroize_derive",
+]
+
+[[package]]
+name = "zeroize_derive"
+version = "1.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3f8f187641dad4f680d25c4bfc4225b418165984179f26ca76ec4fb6441d3a17"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+ "synstructure",
+]
diff --git a/market-contract/Cargo.toml b/market-contract/Cargo.toml
index f0575c8..953eba2 100644
--- a/market-contract/Cargo.toml
+++ b/market-contract/Cargo.toml
@@ -8,7 +8,7 @@ edition = "2021"
 crate-type = ["cdylib", "rlib"]
 
 [dependencies]
-near-sdk = "=4.0.0-pre.4"
+near-sdk = "4.0.0"
 
 [profile.release]
 codegen-units=1
diff --git a/market-contract/src/lib.rs b/market-contract/src/lib.rs
index fa4bd96..0b3235c 100644
--- a/market-contract/src/lib.rs
+++ b/market-contract/src/lib.rs
@@ -20,12 +20,9 @@ mod sale;
 mod sale_views;
 
 //GAS constants to attach to calls
-const GAS_FOR_ROYALTIES: Gas = Gas(115_000_000_000_000);
+const GAS_FOR_RESOLVE_PURCHASE: Gas = Gas(115_000_000_000_000);
 const GAS_FOR_NFT_TRANSFER: Gas = Gas(15_000_000_000_000);
 
-//constant used to attach 0 NEAR to a call
-const NO_DEPOSIT: Balance = 0;
-
 //the minimum storage to have a sale on the contract.
 const STORAGE_PER_SALE: u128 = 1000 * STORAGE_PRICE_PER_BYTE;
 
diff --git a/market-contract/src/sale.rs b/market-contract/src/sale.rs
index 6d723f5..0991bf0 100644
--- a/market-contract/src/sale.rs
+++ b/market-contract/src/sale.rs
@@ -113,30 +113,33 @@ impl Contract {
 
         //initiate a cross contract call to the nft contract. This will transfer the token to the buyer and return
         //a payout object used for the market to distribute funds to the appropriate accounts.
-        ext_contract::nft_transfer_payout(
-            buyer_id.clone(), //purchaser (person to transfer the NFT to)
-            token_id, //token ID to transfer
-            sale.approval_id, //market contract's approval ID in order to transfer the token on behalf of the owner
+        ext_contract::ext(nft_contract_id)
+            // Attach 1 yoctoNEAR with static GAS equal to the GAS for nft transfer. Also attach an unused GAS weight of 1 by default.
+            .with_attached_deposit(1)
+            .with_static_gas(GAS_FOR_NFT_TRANSFER)
+            .nft_transfer_payout(
+                buyer_id.clone(), //purchaser (person to transfer the NFT to)
+                token_id, //token ID to transfer
+                sale.approval_id, //market contract's approval ID in order to transfer the token on behalf of the owner
             "payout from market".to_string(), //memo (to include some context)
             /*
                 the price that the token was purchased for. This will be used in conjunction with the royalty percentages
                 for the token in order to determine how much money should go to which account. 
             */
             price,
-			10, //the maximum amount of accounts the market can payout at once (this is limited by GAS)
-            nft_contract_id, //contract to initiate the cross contract call to
-            1, //yoctoNEAR to attach to the call
-            GAS_FOR_NFT_TRANSFER, //GAS to attach to the call
-        )
+            10, //the maximum amount of accounts the market can payout at once (this is limited by GAS)
+            )
         //after the transfer payout has been initiated, we resolve the promise by calling our own resolve_purchase function. 
         //resolve purchase will take the payout object returned from the nft_transfer_payout and actually pay the accounts
-        .then(ext_self::resolve_purchase(
-            buyer_id, //the buyer and price are passed in incase something goes wrong and we need to refund the buyer
-            price,
-            env::current_account_id(), //we are invoking this function on the current contract
-            NO_DEPOSIT, //don't attach any deposit
-            GAS_FOR_ROYALTIES, //GAS attached to the call to payout royalties
-        ))
+        .then(
+            // No attached deposit with static GAS equal to the GAS for resolving the purchase. Also attach an unused GAS weight of 1 by default.
+            Self::ext(env::current_account_id())
+            .with_static_gas(GAS_FOR_RESOLVE_PURCHASE)
+            .resolve_purchase(
+                buyer_id, //the buyer and price are passed in incase something goes wrong and we need to refund the buyer
+                price,
+            )
+        )
     }
 
     /*
diff --git a/nft-contract/Cargo.lock b/nft-contract/Cargo.lock
index c77d1c8..7cef943 100644
--- a/nft-contract/Cargo.lock
+++ b/nft-contract/Cargo.lock
@@ -10,24 +10,44 @@ checksum = "fe438c63458706e03479442743baae6c88256498e6431708f6dfc520a26515d3"
 
 [[package]]
 name = "ahash"
-version = "0.4.7"
+version = "0.7.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "739f4a8db6605981345c5654f3a85b056ce52f37a39d34da03f25bf2151ea16e"
+checksum = "fcb51a0695d8f838b1ee009b3fbf66bda078cd64590202a864a8f3e8c4315c47"
+dependencies = [
+ "getrandom 0.2.7",
+ "once_cell",
+ "version_check",
+]
 
 [[package]]
-name = "aho-corasick"
-version = "0.7.15"
+name = "arrayref"
+version = "0.3.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7404febffaa47dac81aa44dba71523c9d069b1bdc50a77db41195149e17f68e5"
-dependencies = [
- "memchr",
-]
+checksum = "a4c527152e37cf757a3f78aae5a06fbeefdb07ccc535c980a3208ee3060dd544"
+
+[[package]]
+name = "arrayvec"
+version = "0.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "23b62fc65de8e4e7f52534fb52b0f3ed04746ae267519eef2a83941e8085068b"
+
+[[package]]
+name = "arrayvec"
+version = "0.7.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8da52d66c7071e2e3fa2a1e5c6d088fec47b593032b254f5e980de8ea54454d6"
 
 [[package]]
 name = "autocfg"
-version = "1.0.1"
+version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cdb031dd78e28731d87d56cc8ffef4a8f36ca26c38fe2de700543e627f8a464a"
+checksum = "d468802bab17cbc0cc575e9b053f41e72aa36bfa6b7f55e3529ffa43161b97fa"
+
+[[package]]
+name = "base64"
+version = "0.11.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b41b7ea54a0c9d92199de89e20e58d49f02f8e699814ef3fdf266f6f748d15c7"
 
 [[package]]
 name = "base64"
@@ -35,27 +55,52 @@ version = "0.13.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "904dfeac50f3cdaba28fc6f57fdcddb75f49ed61346676a78c4ffe55877802fd"
 
+[[package]]
+name = "bitvec"
+version = "0.20.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7774144344a4faa177370406a7ff5f1da24303817368584c6206c8303eb07848"
+dependencies = [
+ "funty",
+ "radium",
+ "tap",
+ "wyz",
+]
+
+[[package]]
+name = "blake2"
+version = "0.9.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0a4e37d16930f5459780f5621038b6382b9bb37c19016f39fb6b5808d831f174"
+dependencies = [
+ "crypto-mac",
+ "digest 0.9.0",
+ "opaque-debug",
+]
+
 [[package]]
 name = "block-buffer"
 version = "0.9.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4152116fd6e9dadb291ae18fc1ec3575ed6d84c29642d97890f4b4a3417297e4"
 dependencies = [
- "block-padding",
  "generic-array",
 ]
 
 [[package]]
-name = "block-padding"
-version = "0.2.1"
+name = "block-buffer"
+version = "0.10.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8d696c370c750c948ada61c69a0ee2cbbb9c50b1019ddb86d9317157a99c2cae"
+checksum = "0bf7fe51849ea569fd452f37822f606a5cabb684dc918707a0193fd4664ff324"
+dependencies = [
+ "generic-array",
+]
 
 [[package]]
 name = "borsh"
-version = "0.8.1"
+version = "0.9.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a5a26c53ddf60281f18e7a29b20db7ba3db82a9d81b9650bfaa02d646f50d364"
+checksum = "15bf3650200d8bffa99015595e10f1fbd17de07abbc25bb067da79e769939bfa"
 dependencies = [
  "borsh-derive",
  "hashbrown",
@@ -63,22 +108,22 @@ dependencies = [
 
 [[package]]
 name = "borsh-derive"
-version = "0.8.1"
+version = "0.9.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b637a47728b78a78cd7f4b85bf06d71ef4221840e059a38f048be2422bf673b2"
+checksum = "6441c552f230375d18e3cc377677914d2ca2b0d36e52129fe15450a2dce46775"
 dependencies = [
  "borsh-derive-internal",
  "borsh-schema-derive-internal",
- "proc-macro-crate",
+ "proc-macro-crate 0.1.5",
  "proc-macro2",
  "syn",
 ]
 
 [[package]]
 name = "borsh-derive-internal"
-version = "0.8.1"
+version = "0.9.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d813fa25eb0bed78c36492cff4415f38c760d6de833d255ba9095bd8ebb7d725"
+checksum = "5449c28a7b352f2d1e592a8a28bf139bc71afb0764a14f3c02500935d8c44065"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -87,9 +132,9 @@ dependencies = [
 
 [[package]]
 name = "borsh-schema-derive-internal"
-version = "0.8.1"
+version = "0.9.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dcf78ee4a98c8cb9eba1bac3d3e2a1ea3d7673c719ce691e67b5cbafc472d3b7"
+checksum = "cdbd5696d8bfa21d53d9fe39a714a18538bad11492a42d066dbbc395fb1951c0"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -102,11 +147,39 @@ version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "771fe0050b883fcc3ea2359b1a96bcfbc090b7116eae7c3c512c7a083fdf23d3"
 
+[[package]]
+name = "byte-slice-cast"
+version = "1.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "87c5fdd0166095e1d463fc6cc01aa8ce547ad77a4e84d42eb6762b084e28067e"
+
 [[package]]
 name = "byteorder"
-version = "1.4.2"
+version = "1.4.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ae44d1a3d5a19df61dd0c8beb138458ac2a53a7ac09eba97d55592540004306b"
+checksum = "14c189c53d098945499cdfa7ecc63567cf3886b3332b312a5b4585d8d3a6a610"
+
+[[package]]
+name = "bytesize"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6c58ec36aac5066d5ca17df51b3e70279f5670a72102f5752cb7e7c856adfc70"
+
+[[package]]
+name = "c2-chacha"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d27dae93fe7b1e0424dc57179ac396908c26b035a87234809f5c4dfd1b47dc80"
+dependencies = [
+ "cipher",
+ "ppv-lite86",
+]
+
+[[package]]
+name = "cc"
+version = "1.0.73"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2fff2a6927b3bb87f9595d67196a70493f627687a71d87a0d692242c33f58c11"
 
 [[package]]
 name = "cfg-if"
@@ -121,19 +194,92 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
 
 [[package]]
-name = "cpuid-bool"
-version = "0.1.2"
+name = "chrono"
+version = "0.4.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "670ad68c9088c2a963aaa298cb369688cf3f9465ce5e2d4ca10e6e0098a1ce73"
+dependencies = [
+ "libc",
+ "num-integer",
+ "num-traits",
+ "serde",
+ "time",
+ "winapi",
+]
+
+[[package]]
+name = "cipher"
+version = "0.2.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "12f8e7987cbd042a63249497f41aed09f8e65add917ea6566effbc56578d6801"
+dependencies = [
+ "generic-array",
+]
+
+[[package]]
+name = "convert_case"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6245d59a3e82a7fc217c5828a6692dbc6dfb63a0c8c90495621f7b9d79704a0e"
+
+[[package]]
+name = "cpufeatures"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "59a6001667ab124aebae2a495118e11d30984c3a653e99d86d58971708cf5e4b"
+dependencies = [
+ "libc",
+]
+
+[[package]]
+name = "crunchy"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7a81dae078cea95a014a339291cec439d2f232ebe854a9d672b796c6afafa9b7"
+
+[[package]]
+name = "crypto-common"
+version = "0.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "57952ca27b5e3606ff4dd79b0020231aaf9d6aa76dc05fd30137538c50bd3ce8"
+dependencies = [
+ "generic-array",
+ "typenum",
+]
+
+[[package]]
+name = "crypto-mac"
+version = "0.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8aebca1129a03dc6dc2b127edd729435bbc4a37e1d5f4d7513165089ceb02634"
+checksum = "b584a330336237c1eecd3e94266efb216c56ed91225d634cb2991c5f3fd1aeab"
+dependencies = [
+ "generic-array",
+ "subtle",
+]
+
+[[package]]
+name = "curve25519-dalek"
+version = "3.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "90f9d052967f590a76e62eb387bd0bbb1b000182c3cefe5364db6b7211651bc0"
+dependencies = [
+ "byteorder",
+ "digest 0.9.0",
+ "rand_core 0.5.1",
+ "subtle",
+ "zeroize",
+]
 
 [[package]]
 name = "derive_more"
-version = "0.99.11"
+version = "0.99.17"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "41cb0e6161ad61ed084a36ba71fbba9e3ac5aee3606fb607fe08da6acbcf3d8c"
+checksum = "4fb810d30a7c1953f91334de7244731fc3f3c10d7fe163338a35b9f640960321"
 dependencies = [
+ "convert_case",
  "proc-macro2",
  "quote",
+ "rustc_version",
  "syn",
 ]
 
@@ -146,70 +292,153 @@ dependencies = [
  "generic-array",
 ]
 
+[[package]]
+name = "digest"
+version = "0.10.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f2fb860ca6fafa5552fb6d0e816a69c8e49f0908bf524e30a90d97c85892d506"
+dependencies = [
+ "block-buffer 0.10.2",
+ "crypto-common",
+]
+
+[[package]]
+name = "easy-ext"
+version = "0.2.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "53aff6fdc1b181225acdcb5b14c47106726fd8e486707315b1b138baed68ee31"
+
+[[package]]
+name = "ed25519"
+version = "1.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1e9c280362032ea4203659fc489832d0204ef09f247a0506f170dafcac08c369"
+dependencies = [
+ "signature",
+]
+
+[[package]]
+name = "ed25519-dalek"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c762bae6dcaf24c4c84667b8579785430908723d5c889f469d76a41d59cc7a9d"
+dependencies = [
+ "curve25519-dalek",
+ "ed25519",
+ "rand 0.7.3",
+ "serde",
+ "sha2 0.9.9",
+ "zeroize",
+]
+
+[[package]]
+name = "fixed-hash"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cfcf0ed7fe52a17a03854ec54a9f76d6d84508d1c0e66bc1793301c73fc8493c"
+dependencies = [
+ "byteorder",
+ "rand 0.8.5",
+ "rustc-hex",
+ "static_assertions",
+]
+
+[[package]]
+name = "funty"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fed34cd105917e91daa4da6b3728c47b068749d6a62c59811f06ed2ac71d9da7"
+
 [[package]]
 name = "generic-array"
-version = "0.14.4"
+version = "0.14.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "501466ecc8a30d1d3b7fc9229b122b2ce8ed6e9d9223f1138d4babb253e51817"
+checksum = "fd48d33ec7f05fbfa152300fdad764757cbded343c1aa1cff2fbaf4134851803"
 dependencies = [
  "typenum",
  "version_check",
 ]
 
+[[package]]
+name = "getrandom"
+version = "0.1.16"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8fc3cb4d91f53b50155bdcfd23f6a4c39ae1969c2ae85982b135750cccaf5fce"
+dependencies = [
+ "cfg-if 1.0.0",
+ "libc",
+ "wasi 0.9.0+wasi-snapshot-preview1",
+]
+
+[[package]]
+name = "getrandom"
+version = "0.2.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4eb1a864a501629691edf6c15a593b7a51eebaa1e8468e9ddc623de7c9b58ec6"
+dependencies = [
+ "cfg-if 1.0.0",
+ "libc",
+ "wasi 0.11.0+wasi-snapshot-preview1",
+]
+
 [[package]]
 name = "hashbrown"
-version = "0.9.1"
+version = "0.11.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d7afe4a420e3fe79967a00898cc1f4db7c8a49a9333a29f8a4bd76a253d5cd04"
+checksum = "ab5ef0d4909ef3724cc8cce6ccc8572c5c817592e9285f5464f8e86f8bd3726e"
 dependencies = [
  "ahash",
 ]
 
+[[package]]
+name = "heck"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2540771e65fc8cb83cd6e8a237f70c319bd5c29f78ed1084ba5d50eeac86f7f9"
+
 [[package]]
 name = "hex"
-version = "0.4.2"
+version = "0.4.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "644f9158b2f133fd50f5fb3242878846d9eb792e445c893805ff0e3824006e35"
+checksum = "7f24254aa9a54b5c858eaee2f5bccdb46aaf0e486a595ed5fd8f86ba55232a70"
 
 [[package]]
-name = "indexmap"
-version = "1.6.1"
+name = "impl-codec"
+version = "0.5.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4fb1fa934250de4de8aef298d81c729a7d33d8c239daa3a7575e6b92bfc7313b"
+checksum = "161ebdfec3c8e3b52bf61c4f3550a1eea4f9579d10dc1b936f3171ebdcd6c443"
 dependencies = [
- "autocfg",
- "hashbrown",
+ "parity-scale-codec",
 ]
 
 [[package]]
-name = "itoa"
-version = "0.4.7"
+name = "impl-trait-for-tuples"
+version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dd25036021b0de88a0aff6b850051563c6516d0bf53f8638938edbb9de732736"
+checksum = "11d7a9f6330b71fea57921c9b61c47ee6e84f72d394754eff6163ae67e7395eb"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
 
 [[package]]
-name = "keccak"
-version = "0.1.0"
+name = "itoa"
+version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "67c21572b4949434e4fc1e1978b99c5f77064153c59d998bf13ecd96fb5ecba7"
+checksum = "112c678d4050afce233f4f2852bb2eb519230b3cf12f33585275537d7e41578d"
 
 [[package]]
-name = "lazy_static"
-version = "1.4.0"
+name = "keccak"
+version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
+checksum = "f9b7d56ba4a8344d6be9729995e6b06f928af29998cdf79fe390cbf6b1fee838"
 
 [[package]]
 name = "libc"
-version = "0.2.86"
+version = "0.2.126"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b7282d924be3275cec7f6756ff4121987bc6481325397dde6ba3e7802b1a8b1c"
-
-[[package]]
-name = "memchr"
-version = "2.3.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0ee1c47aaa256ecabcaea351eae4a9b01ef39ed810004e298d2511ed284b1525"
+checksum = "349d5a591cd28b49e1d1037471617a32ddcda5731b99419008085f72d5a53836"
 
 [[package]]
 name = "memory_units"
@@ -218,69 +447,121 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8452105ba047068f40ff7093dd1d9da90898e63dd61736462e9cdda6a90ad3c3"
 
 [[package]]
-name = "near-primitives-core"
-version = "0.4.0"
+name = "near-account-id"
+version = "0.13.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "de83d74a9241be8cc4eb3055216966b58bf8c463e8e285c0dc553925acdd19fa"
+dependencies = [
+ "borsh",
+ "serde",
+]
+
+[[package]]
+name = "near-crypto"
+version = "0.13.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c2b3fb5acf3a494aed4e848446ef2d6ebb47dbe91c681105d4d1786c2ee63e52"
+checksum = "b8ecf0b8b31aa7f4e60f629f72213a2617ca4a5f45cd1ae9ed2cf7cecfebdbb7"
 dependencies = [
- "base64",
+ "arrayref",
+ "blake2",
  "borsh",
  "bs58",
+ "c2-chacha",
+ "curve25519-dalek",
  "derive_more",
+ "ed25519-dalek",
+ "libc",
+ "near-account-id",
+ "once_cell",
+ "parity-secp256k1",
+ "primitive-types",
+ "rand 0.7.3",
+ "rand_core 0.5.1",
+ "serde",
+ "serde_json",
+ "subtle",
+ "thiserror",
+]
+
+[[package]]
+name = "near-primitives"
+version = "0.13.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0a2ba19282e79a4485a77736b679d276b09870bbf8042a18e0f0ae36347489c5"
+dependencies = [
+ "borsh",
+ "byteorder",
+ "bytesize",
+ "chrono",
+ "derive_more",
+ "easy-ext",
  "hex",
- "lazy_static",
+ "near-crypto",
+ "near-primitives-core",
+ "near-rpc-error-macro",
+ "near-vm-errors",
  "num-rational",
+ "once_cell",
+ "primitive-types",
+ "rand 0.7.3",
+ "reed-solomon-erasure",
  "serde",
  "serde_json",
- "sha2",
+ "smart-default",
+ "strum",
+ "thiserror",
 ]
 
 [[package]]
-name = "near-rpc-error-core"
-version = "0.1.0"
+name = "near-primitives-core"
+version = "0.13.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ffa8dbf8437a28ac40fcb85859ab0d0b8385013935b000c7a51ae79631dd74d9"
+checksum = "bb561feb392bb8c4f540256073446e6689af087bf6356e8dddcf75fc279f201f"
 dependencies = [
- "proc-macro2",
- "quote",
+ "base64 0.11.0",
+ "borsh",
+ "bs58",
+ "derive_more",
+ "near-account-id",
+ "num-rational",
  "serde",
- "serde_json",
- "syn",
+ "sha2 0.10.2",
+ "strum",
 ]
 
 [[package]]
-name = "near-rpc-error-macro"
-version = "0.1.0"
+name = "near-rpc-error-core"
+version = "0.13.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0c6111d713e90c7c551dee937f4a06cb9ea2672243455a4454cc7566387ba2d9"
+checksum = "77fdd7ea8d8f786878651c37691515d5053f827ae60894aa40c16882b78f77c9"
 dependencies = [
- "near-rpc-error-core",
- "proc-macro2",
  "quote",
  "serde",
- "serde_json",
  "syn",
 ]
 
 [[package]]
-name = "near-runtime-utils"
-version = "4.0.0-pre.1"
+name = "near-rpc-error-macro"
+version = "0.13.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a48d80c4ca1d4cf99bc16490e1e3d49826c150dfc4410ac498918e45c7d98e07"
+checksum = "e521842b6ae864dfe5391afbbe2df9e9d8427c26e9333b2e0b65cd42094f7607"
 dependencies = [
- "lazy_static",
- "regex",
+ "near-rpc-error-core",
+ "serde",
+ "syn",
 ]
 
 [[package]]
 name = "near-sdk"
-version = "4.0.0-pre.4"
+version = "4.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "10f570e260eae9169dd5ffe0764728b872c2df79b8786dfb5e57183bd383908e"
+checksum = "bda34e06e28fb9a09ac54efbdc49f0c9308780fc932aaa81c49c493fde974045"
 dependencies = [
- "base64",
+ "base64 0.13.0",
  "borsh",
  "bs58",
+ "near-crypto",
+ "near-primitives",
  "near-primitives-core",
  "near-sdk-macros",
  "near-sys",
@@ -292,9 +573,9 @@ dependencies = [
 
 [[package]]
 name = "near-sdk-macros"
-version = "4.0.0-pre.4"
+version = "4.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "65ddca18086f1ab14ce8541e0c23f503a322d45914f2fe08f571844045d32bde"
+checksum = "72064fcc15a623a0d40a6c199ea5cbdc30a83cae4816889d46f218acf31bfba8"
 dependencies = [
  "Inflector",
  "proc-macro2",
@@ -304,37 +585,40 @@ dependencies = [
 
 [[package]]
 name = "near-sys"
-version = "0.1.0"
+version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f6a7aa3f46fac44416d8a93d14f30a562c4d730a1c6bf14bffafab5f475c244a"
+checksum = "e307313276eaeced2ca95740b5639e1f3125b7c97f0a1151809d105f1aa8c6d3"
 
 [[package]]
 name = "near-vm-errors"
-version = "4.0.0-pre.1"
+version = "0.13.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e281d8730ed8cb0e3e69fb689acee6b93cdb43824cd69a8ffd7e1bfcbd1177d7"
+checksum = "0e02faf2bc1f6ef82b965cfe44389808fb5594f7aca4b596766117f4ce74df20"
 dependencies = [
  "borsh",
- "hex",
+ "near-account-id",
  "near-rpc-error-macro",
  "serde",
 ]
 
 [[package]]
 name = "near-vm-logic"
-version = "4.0.0-pre.1"
+version = "0.13.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e11cb28a2d07f37680efdaf860f4c9802828c44fc50c08009e7884de75d982c5"
+checksum = "f024d90451cd3c24d7a0a5cabf3636b192a60eb8e3ff0456f6c18b91152c346d"
 dependencies = [
- "base64",
+ "base64 0.13.0",
  "borsh",
  "bs58",
  "byteorder",
+ "near-account-id",
+ "near-crypto",
+ "near-primitives",
  "near-primitives-core",
- "near-runtime-utils",
  "near-vm-errors",
+ "ripemd",
  "serde",
- "sha2",
+ "sha2 0.10.2",
  "sha3",
 ]
 
@@ -348,9 +632,9 @@ dependencies = [
 
 [[package]]
 name = "num-bigint"
-version = "0.3.1"
+version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5e9a41747ae4633fce5adffb4d2e81ffc5e89593cb19917f8fb2cc5ff76507bf"
+checksum = "5f6f7833f2cbf2360a6cfd58cd41a53aa7a90bd4c202f5b1c7dd2ed73c57b2c3"
 dependencies = [
  "autocfg",
  "num-integer",
@@ -359,9 +643,9 @@ dependencies = [
 
 [[package]]
 name = "num-integer"
-version = "0.1.44"
+version = "0.1.45"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d2cc698a63b549a70bc047073d2949cce27cd1c7b0a4a862d08a8031bc2801db"
+checksum = "225d3389fb3509a24c93f5c29eb6bde2586b98d9f016636dff58d7c6f7569cd9"
 dependencies = [
  "autocfg",
  "num-traits",
@@ -382,18 +666,18 @@ dependencies = [
 
 [[package]]
 name = "num-traits"
-version = "0.2.14"
+version = "0.2.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9a64b1ec5cda2586e284722486d802acf1f7dbdc623e2bfc57e65ca1cd099290"
+checksum = "578ede34cf02f8924ab9447f50c28075b4d3e5b269972345e7e0372b38c6cdcd"
 dependencies = [
  "autocfg",
 ]
 
 [[package]]
 name = "once_cell"
-version = "1.5.2"
+version = "1.12.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "13bd41f508810a131401606d54ac32a467c97172d74ba7662562ebba5ad07fa0"
+checksum = "7709cef83f0c1f58f666e746a08b21e0085f7440fa6a29cc194d68aac97a4225"
 
 [[package]]
 name = "opaque-debug"
@@ -401,6 +685,61 @@ version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "624a8340c38c1b80fd549087862da4ba43e08858af025b236e509b6649fc13d5"
 
+[[package]]
+name = "parity-scale-codec"
+version = "2.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "373b1a4c1338d9cd3d1fa53b3a11bdab5ab6bd80a20f7f7becd76953ae2be909"
+dependencies = [
+ "arrayvec 0.7.2",
+ "bitvec",
+ "byte-slice-cast",
+ "impl-trait-for-tuples",
+ "parity-scale-codec-derive",
+ "serde",
+]
+
+[[package]]
+name = "parity-scale-codec-derive"
+version = "2.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1557010476e0595c9b568d16dcfb81b93cdeb157612726f5170d31aa707bed27"
+dependencies = [
+ "proc-macro-crate 1.1.3",
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "parity-secp256k1"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4fca4f82fccae37e8bbdaeb949a4a218a1bbc485d11598f193d2a908042e5fc1"
+dependencies = [
+ "arrayvec 0.5.2",
+ "cc",
+ "cfg-if 0.1.10",
+ "rand 0.7.3",
+]
+
+[[package]]
+name = "ppv-lite86"
+version = "0.2.16"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "eb9f9e6e233e5c4a35559a617bf40a4ec447db2e84c20b55a6f83167b7e57872"
+
+[[package]]
+name = "primitive-types"
+version = "0.10.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "05e4722c697a58a99d5d06a08c30821d7c082a4632198de1eaa5a6c22ef42373"
+dependencies = [
+ "fixed-hash",
+ "impl-codec",
+ "uint",
+]
+
 [[package]]
 name = "proc-macro-crate"
 version = "0.1.5"
@@ -410,62 +749,176 @@ dependencies = [
  "toml",
 ]
 
+[[package]]
+name = "proc-macro-crate"
+version = "1.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e17d47ce914bf4de440332250b0edd23ce48c005f59fab39d3335866b114f11a"
+dependencies = [
+ "thiserror",
+ "toml",
+]
+
 [[package]]
 name = "proc-macro2"
-version = "1.0.24"
+version = "1.0.39"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1e0704ee1a7e00d7bb417d0770ea303c1bccbabf0ef1667dae92b5967f5f8a71"
+checksum = "c54b25569025b7fc9651de43004ae593a75ad88543b17178aa5e1b9c4f15f56f"
 dependencies = [
- "unicode-xid",
+ "unicode-ident",
 ]
 
 [[package]]
 name = "quote"
-version = "1.0.8"
+version = "1.0.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "991431c3519a3f36861882da93630ce66b52918dcf1b8e2fd66b397fc96f28df"
+checksum = "a1feb54ed693b93a84e14094943b84b7c4eae204c512b7ccb95ab0c66d278ad1"
 dependencies = [
  "proc-macro2",
 ]
 
 [[package]]
-name = "regex"
-version = "1.4.3"
+name = "radium"
+version = "0.6.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "643f8f41a8ebc4c5dc4515c82bb8abd397b527fc20fd681b7c011c2aee5d44fb"
+
+[[package]]
+name = "rand"
+version = "0.7.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6a6b1679d49b24bbfe0c803429aa1874472f50d9b363131f0e89fc356b544d03"
+dependencies = [
+ "getrandom 0.1.16",
+ "libc",
+ "rand_chacha 0.2.2",
+ "rand_core 0.5.1",
+ "rand_hc",
+]
+
+[[package]]
+name = "rand"
+version = "0.8.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "34af8d1a0e25924bc5b7c43c079c942339d8f0a8b57c39049bef581b46327404"
+dependencies = [
+ "libc",
+ "rand_chacha 0.3.1",
+ "rand_core 0.6.3",
+]
+
+[[package]]
+name = "rand_chacha"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f4c8ed856279c9737206bf725bf36935d8666ead7aa69b52be55af369d193402"
+dependencies = [
+ "ppv-lite86",
+ "rand_core 0.5.1",
+]
+
+[[package]]
+name = "rand_chacha"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e6c10a63a0fa32252be49d21e7709d4d4baf8d231c2dbce1eaa8141b9b127d88"
+dependencies = [
+ "ppv-lite86",
+ "rand_core 0.6.3",
+]
+
+[[package]]
+name = "rand_core"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "90bde5296fc891b0cef12a6d03ddccc162ce7b2aff54160af9338f8d40df6d19"
+dependencies = [
+ "getrandom 0.1.16",
+]
+
+[[package]]
+name = "rand_core"
+version = "0.6.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d34f1408f55294453790c48b2f1ebbb1c5b4b7563eb1f418bcfcfdbb06ebb4e7"
+dependencies = [
+ "getrandom 0.2.7",
+]
+
+[[package]]
+name = "rand_hc"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ca3129af7b92a17112d59ad498c6f81eaf463253766b90396d39ea7a39d6613c"
+dependencies = [
+ "rand_core 0.5.1",
+]
+
+[[package]]
+name = "reed-solomon-erasure"
+version = "4.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a415a013dd7c5d4221382329a5a3482566da675737494935cbbbcdec04662f9d"
+dependencies = [
+ "smallvec",
+]
+
+[[package]]
+name = "ripemd"
+version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d9251239e129e16308e70d853559389de218ac275b515068abc96829d05b948a"
+checksum = "1facec54cb5e0dc08553501fa740091086d0259ad0067e0d4103448e4cb22ed3"
 dependencies = [
- "aho-corasick",
- "memchr",
- "regex-syntax",
- "thread_local",
+ "digest 0.10.3",
 ]
 
 [[package]]
-name = "regex-syntax"
-version = "0.6.22"
+name = "rustc-hex"
+version = "2.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b5eb417147ba9860a96cfe72a0b93bf88fee1744b5636ec99ab20c1aa9376581"
+checksum = "3e75f6a532d0fd9f7f13144f392b6ad56a32696bfcd9c78f797f16bbb6f072d6"
+
+[[package]]
+name = "rustc_version"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bfa0f585226d2e68097d4f95d113b15b83a82e819ab25717ec0590d9584ef366"
+dependencies = [
+ "semver",
+]
+
+[[package]]
+name = "rustversion"
+version = "1.0.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f2cc38e8fa666e2de3c4aba7edeb5ffc5246c1c2ed0e3d17e560aeeba736b23f"
 
 [[package]]
 name = "ryu"
-version = "1.0.5"
+version = "1.0.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "71d301d4193d031abdd79ff7e3dd721168a9572ef3fe51a1517aba235bd8f86e"
+checksum = "f3f6f92acf49d1b98f7a81226834412ada05458b7364277387724a237f062695"
+
+[[package]]
+name = "semver"
+version = "1.0.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a41d061efea015927ac527063765e73601444cdc344ba855bc7bd44578b25e1c"
 
 [[package]]
 name = "serde"
-version = "1.0.118"
+version = "1.0.137"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "06c64263859d87aa2eb554587e2d23183398d617427327cf2b3d0ed8c69e4800"
+checksum = "61ea8d54c77f8315140a05f4c7237403bf38b72704d031543aa1d16abbf517d1"
 dependencies = [
  "serde_derive",
 ]
 
 [[package]]
 name = "serde_derive"
-version = "1.0.118"
+version = "1.0.137"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c84d3526699cd55261af4b941e4e725444df67aa4f9e6a3564f18030d12672df"
+checksum = "1f26faba0c3959972377d3b2d306ee9f71faee9714294e41bb777f83f88578be"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -474,11 +927,10 @@ dependencies = [
 
 [[package]]
 name = "serde_json"
-version = "1.0.62"
+version = "1.0.81"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ea1c6153794552ea7cf7cf63b1231a25de00ec90db326ba6264440fa08e31486"
+checksum = "9b7ce2b32a1aed03c558dc61a5cd328f15aff2dbc17daad8fb8af04d2100e15c"
 dependencies = [
- "indexmap",
  "itoa",
  "ryu",
  "serde",
@@ -486,75 +938,217 @@ dependencies = [
 
 [[package]]
 name = "sha2"
-version = "0.9.3"
+version = "0.9.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fa827a14b29ab7f44778d14a88d3cb76e949c45083f7dbfa507d0cb699dc12de"
+checksum = "4d58a1e1bf39749807d89cf2d98ac2dfa0ff1cb3faa38fbb64dd88ac8013d800"
 dependencies = [
- "block-buffer",
+ "block-buffer 0.9.0",
  "cfg-if 1.0.0",
- "cpuid-bool",
- "digest",
+ "cpufeatures",
+ "digest 0.9.0",
  "opaque-debug",
 ]
 
+[[package]]
+name = "sha2"
+version = "0.10.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "55deaec60f81eefe3cce0dc50bda92d6d8e88f2a27df7c5033b42afeb1ed2676"
+dependencies = [
+ "cfg-if 1.0.0",
+ "cpufeatures",
+ "digest 0.10.3",
+]
+
 [[package]]
 name = "sha3"
-version = "0.9.1"
+version = "0.10.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f81199417d4e5de3f04b1e871023acea7389672c4135918f05aa9cbf2f2fa809"
+checksum = "881bf8156c87b6301fc5ca6b27f11eeb2761224c7081e69b409d5a1951a70c86"
 dependencies = [
- "block-buffer",
- "digest",
+ "digest 0.10.3",
  "keccak",
- "opaque-debug",
 ]
 
+[[package]]
+name = "signature"
+version = "1.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f054c6c1a6e95179d6f23ed974060dcefb2d9388bb7256900badad682c499de4"
+
+[[package]]
+name = "smallvec"
+version = "1.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f2dd574626839106c320a323308629dcb1acfc96e32a8cba364ddc61ac23ee83"
+
+[[package]]
+name = "smart-default"
+version = "0.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "133659a15339456eeeb07572eb02a91c91e9815e9cbc89566944d2c8d3efdbf6"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "static_assertions"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a2eb9349b6444b326872e140eb1cf5e7c522154d69e7a0ffb0fb81c06b37543f"
+
+[[package]]
+name = "strum"
+version = "0.24.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "063e6045c0e62079840579a7e47a355ae92f60eb74daaf156fb1e84ba164e63f"
+dependencies = [
+ "strum_macros",
+]
+
+[[package]]
+name = "strum_macros"
+version = "0.24.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9550962e7cf70d9980392878dfaf1dcc3ece024f4cf3bf3c46b978d0bad61d6c"
+dependencies = [
+ "heck",
+ "proc-macro2",
+ "quote",
+ "rustversion",
+ "syn",
+]
+
+[[package]]
+name = "subtle"
+version = "2.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6bdef32e8150c2a081110b42772ffe7d7c9032b606bc226c8260fd97e0976601"
+
 [[package]]
 name = "syn"
-version = "1.0.57"
+version = "1.0.96"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4211ce9909eb971f111059df92c45640aad50a619cf55cd76476be803c4c68e6"
+checksum = "0748dd251e24453cb8717f0354206b91557e4ec8703673a4b30208f2abaf1ebf"
 dependencies = [
  "proc-macro2",
  "quote",
+ "unicode-ident",
+]
+
+[[package]]
+name = "synstructure"
+version = "0.12.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f36bdaa60a83aca3921b5259d5400cbf5e90fc51931376a9bd4a0eb79aa7210f"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
  "unicode-xid",
 ]
 
 [[package]]
-name = "thread_local"
-version = "1.1.3"
+name = "tap"
+version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8018d24e04c95ac8790716a5987d0fec4f8b27249ffa0f7d33f1369bdfb88cbd"
+checksum = "55937e1799185b12863d447f42597ed69d9928686b8d88a1df17376a097d8369"
+
+[[package]]
+name = "thiserror"
+version = "1.0.31"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bd829fe32373d27f76265620b5309d0340cb8550f523c1dda251d6298069069a"
 dependencies = [
- "once_cell",
+ "thiserror-impl",
+]
+
+[[package]]
+name = "thiserror-impl"
+version = "1.0.31"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0396bc89e626244658bef819e22d0cc459e795a5ebe878e6ec336d1674a8d79a"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "time"
+version = "0.1.44"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6db9e6914ab8b1ae1c260a4ae7a49b6c5611b40328a735b21862567685e73255"
+dependencies = [
+ "libc",
+ "wasi 0.10.0+wasi-snapshot-preview1",
+ "winapi",
 ]
 
 [[package]]
 name = "toml"
-version = "0.5.8"
+version = "0.5.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a31142970826733df8241ef35dc040ef98c679ab14d7c3e54d827099b3acecaa"
+checksum = "8d82e1a7758622a465f8cee077614c73484dac5b836c02ff6a40d5d1010324d7"
 dependencies = [
  "serde",
 ]
 
 [[package]]
 name = "typenum"
-version = "1.12.0"
+version = "1.15.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dcf81ac59edc17cc8697ff311e8f5ef2d99fcbd9817b34cec66f90b6c3dfd987"
+
+[[package]]
+name = "uint"
+version = "0.9.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "12f03af7ccf01dd611cc450a0d10dbc9b745770d096473e2faf0ca6e2d66d1e0"
+dependencies = [
+ "byteorder",
+ "crunchy",
+ "hex",
+ "static_assertions",
+]
+
+[[package]]
+name = "unicode-ident"
+version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "373c8a200f9e67a0c95e62a4f52fbf80c23b4381c05a17845531982fa99e6b33"
+checksum = "5bd2fe26506023ed7b5e1e315add59d6f584c621d037f9368fea9cfb988f368c"
 
 [[package]]
 name = "unicode-xid"
-version = "0.2.1"
+version = "0.2.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f7fe0bb3479651439c9112f72b6c505038574c9fbb575ed1bf3b797fa39dd564"
+checksum = "957e51f3646910546462e67d5f7599b9e4fb8acdd304b087a6494730f9eebf04"
 
 [[package]]
 name = "version_check"
-version = "0.9.2"
+version = "0.9.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "49874b5167b65d7193b8aba1567f5c7d93d001cafc34600cee003eda787e483f"
+
+[[package]]
+name = "wasi"
+version = "0.9.0+wasi-snapshot-preview1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cccddf32554fecc6acb585f82a32a72e28b48f8c4c1883ddfeeeaa96f7d8e519"
+
+[[package]]
+name = "wasi"
+version = "0.10.0+wasi-snapshot-preview1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b5a972e5669d67ba988ce3dc826706fb0a8b01471c088cb0b6110b805cc36aed"
+checksum = "1a143597ca7c7793eff794def352d41792a93c481eb1042423ff7ff72ba2c31f"
+
+[[package]]
+name = "wasi"
+version = "0.11.0+wasi-snapshot-preview1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9c8d87e72b64a3b4db28d11ce29237c246188f4f51057d65a7eab63b7987e423"
 
 [[package]]
 name = "wee_alloc"
@@ -589,3 +1183,30 @@ name = "winapi-x86_64-pc-windows-gnu"
 version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
+
+[[package]]
+name = "wyz"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "85e60b0d1b5f99db2556934e21937020776a5d31520bf169e851ac44e6420214"
+
+[[package]]
+name = "zeroize"
+version = "1.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4756f7db3f7b5574938c3eb1c117038b8e07f95ee6718c0efad4ac21508f1efd"
+dependencies = [
+ "zeroize_derive",
+]
+
+[[package]]
+name = "zeroize_derive"
+version = "1.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3f8f187641dad4f680d25c4bfc4225b418165984179f26ca76ec4fb6441d3a17"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+ "synstructure",
+]
diff --git a/nft-contract/Cargo.toml b/nft-contract/Cargo.toml
index 343ecb0..9484b1f 100644
--- a/nft-contract/Cargo.toml
+++ b/nft-contract/Cargo.toml
@@ -8,7 +8,7 @@ edition = "2021"
 crate-type = ["cdylib", "rlib"]
 
 [dependencies]
-near-sdk = "=4.0.0-pre.4"
+near-sdk = "4.0.0"
 serde_json = "1.0"
 
 [profile.release]
diff --git a/nft-contract/src/approval.rs b/nft-contract/src/approval.rs
index e22368e..a58d8a1 100644
--- a/nft-contract/src/approval.rs
+++ b/nft-contract/src/approval.rs
@@ -1,8 +1,5 @@
 use crate::*;
-use near_sdk::{ext_contract, Gas};
-
-const GAS_FOR_NFT_APPROVE: Gas = Gas(10_000_000_000_000);
-const NO_DEPOSIT: Balance = 0;
+use near_sdk::{ext_contract};
 
 pub trait NonFungibleTokenCore {
     //approve an account ID to transfer a token on your behalf
@@ -87,16 +84,14 @@ impl NonFungibleTokenCore for Contract {
         //if some message was passed into the function, we initiate a cross contract call on the
         //account we're giving access to. 
         if let Some(msg) = msg {
-            ext_non_fungible_approval_receiver::nft_on_approve(
-                token_id,
-                token.owner_id,
-                approval_id,
-                msg,
-                account_id, //contract account we're calling
-                NO_DEPOSIT, //NEAR deposit we attach to the call
-                env::prepaid_gas() - GAS_FOR_NFT_APPROVE, //GAS we're attaching
-            )
-            .as_return(); // Returning this promise
+            // Defaulting GAS weight to 1, no attached deposit, and no static GAS to attach.
+            ext_non_fungible_approval_receiver::ext(account_id)
+                .nft_on_approve(
+                    token_id, 
+                    token.owner_id, 
+                    approval_id, 
+                    msg
+                ).as_return();
         }
     }
 
diff --git a/nft-contract/src/internal.rs b/nft-contract/src/internal.rs
index e830a36..465fa5d 100644
--- a/nft-contract/src/internal.rs
+++ b/nft-contract/src/internal.rs
@@ -234,7 +234,7 @@ impl Contract {
         // Log the serialized json.
         env::log_str(&nft_transfer_log.to_string());
         
-        //return the preivous token object that was transferred.
+        //return the previous token object that was transferred.
         token
     }
 } 
\ No newline at end of file
diff --git a/nft-contract/src/metadata.rs b/nft-contract/src/metadata.rs
index 55ef463..ec13a70 100644
--- a/nft-contract/src/metadata.rs
+++ b/nft-contract/src/metadata.rs
@@ -12,7 +12,7 @@ pub struct Payout {
 pub struct NFTContractMetadata {
     pub spec: String,              // required, essentially a version like "nft-1.0.0"
     pub name: String,              // required, ex. "Mosaics"
-    pub symbol: String,            // required, ex. "MOSIAC"
+    pub symbol: String,            // required, ex. "MOSAIC"
     pub icon: Option<String>,      // Data URL
     pub base_uri: Option<String>, // Centralized gateway known to have reliable access to decentralized storage assets referenced by `reference` or `media` URLs
     pub reference: Option<String>, // URL to a JSON file with more info
diff --git a/nft-contract/src/nft_core.rs b/nft-contract/src/nft_core.rs
index 41e580f..c4fc19b 100644
--- a/nft-contract/src/nft_core.rs
+++ b/nft-contract/src/nft_core.rs
@@ -2,9 +2,7 @@ use crate::*;
 use near_sdk::{ext_contract, Gas, PromiseResult};
 
 const GAS_FOR_RESOLVE_TRANSFER: Gas = Gas(10_000_000_000_000);
-const GAS_FOR_NFT_TRANSFER_CALL: Gas = Gas(25_000_000_000_000 + GAS_FOR_RESOLVE_TRANSFER.0);
-const MIN_GAS_FOR_NFT_TRANSFER_CALL: Gas = Gas(100_000_000_000_000);
-const NO_DEPOSIT: Balance = 0;
+const GAS_FOR_NFT_ON_TRANSFER: Gas = Gas(25_000_000_000_000);
 
 pub trait NonFungibleTokenCore {
     //transfers an NFT to a receiver ID
@@ -46,27 +44,6 @@ trait NonFungibleTokenReceiver {
     ) -> Promise;
 }
 
-#[ext_contract(ext_self)]
-trait NonFungibleTokenResolver {
-    /*
-        resolves the promise of the cross contract call to the receiver contract
-        this is stored on THIS contract and is meant to analyze what happened in the cross contract call when nft_on_transfer was called
-        as part of the nft_transfer_call method
-    */
-    fn nft_resolve_transfer(
-        &mut self,
-        //we introduce an authorized ID for logging the transfer event
-        authorized_id: Option<String>,
-        owner_id: AccountId,
-        receiver_id: AccountId,
-        token_id: TokenId,
-        //we introduce the approval map so we can keep track of what the approvals were before the transfer
-        approved_account_ids: HashMap<AccountId, u64>,
-        //we introduce a memo for logging the transfer event
-        memo: Option<String>,
-    ) -> bool;
-}
-
 /*
     resolves the promise of the cross contract call to the receiver contract
     this is stored on THIS contract and is meant to analyze what happened in the cross contract call when nft_on_transfer was called
@@ -121,7 +98,7 @@ impl NonFungibleTokenCore for Contract {
         );
     }
 
-    //implementation of the transfer call method. This will transfer the NFT and call a method on the reciver_id contract
+    //implementation of the transfer call method. This will transfer the NFT and call a method on the receiver_id contract
     #[payable]
     fn nft_transfer_call(
         &mut self,
@@ -135,21 +112,6 @@ impl NonFungibleTokenCore for Contract {
         //assert that the user attached exactly 1 yocto for security reasons. 
         assert_one_yocto();
 
-        //get the GAS attached to the call
-        let attached_gas = env::prepaid_gas();
-
-        /*
-            make sure that the attached gas is greater than the minimum GAS for NFT transfer call.
-            This is to ensure that the cross contract call to nft_on_transfer won't cause a prepaid GAS error.
-            If this happens, the event will be logged in internal_transfer but the actual transfer logic will be
-            reverted due to the panic. This will result in the databases thinking the NFT belongs to the wrong person.
-        */
-        assert!(
-            attached_gas >= MIN_GAS_FOR_NFT_TRANSFER_CALL,
-            "You cannot attach less than {:?} Gas to nft_transfer_call",
-            MIN_GAS_FOR_NFT_TRANSFER_CALL
-        );
-
         //get the sender ID 
         let sender_id = env::predecessor_account_id();
 
@@ -170,27 +132,29 @@ impl NonFungibleTokenCore for Contract {
         }
 
         // Initiating receiver's call and the callback
-        ext_non_fungible_token_receiver::nft_on_transfer(
-            sender_id,
-            previous_token.owner_id.clone(),
-            token_id.clone(),
-            msg,
-            receiver_id.clone(), //contract account to make the call to
-            NO_DEPOSIT, //attached deposit
-            env::prepaid_gas() - GAS_FOR_NFT_TRANSFER_CALL, //attached GAS
-        )
-        //we then resolve the promise and call nft_resolve_transfer on our own contract
-        .then(ext_self::nft_resolve_transfer(
-            authorized_id, // we introduce an authorized ID so that we can log the transfer
-            previous_token.owner_id,
-            receiver_id,
-            token_id,
-            previous_token.approved_account_ids,
-            memo, // we introduce a memo for logging in the events standard
-            env::current_account_id(), //contract account to make the call to
-            NO_DEPOSIT, //attached deposit
-            GAS_FOR_RESOLVE_TRANSFER, //GAS attached to the call
-        )).into()
+        // Defaulting GAS weight to 1, no attached deposit, and static GAS equal to the GAS for nft on transfer.
+        ext_non_fungible_token_receiver::ext(receiver_id.clone())
+            .with_static_gas(GAS_FOR_NFT_ON_TRANSFER)
+            .nft_on_transfer(
+                sender_id, 
+                previous_token.owner_id.clone(), 
+                token_id.clone(), 
+                msg
+            )
+        // We then resolve the promise and call nft_resolve_transfer on our own contract
+        .then(
+            // Defaulting GAS weight to 1, no attached deposit, and static GAS equal to the GAS for resolve transfer
+            Self::ext(env::current_account_id())
+                .with_static_gas(GAS_FOR_RESOLVE_TRANSFER)
+                .nft_resolve_transfer(
+                    authorized_id, // we introduce an authorized ID so that we can log the transfer
+                    previous_token.owner_id,
+                    receiver_id,
+                    token_id,
+                    previous_token.approved_account_ids,
+                    memo, // we introduce a memo for logging in the events standard
+                )
+        ).into()
     }
 
     //get the information for a specific token ID
diff --git a/out/main.wasm b/out/main.wasm
index 622cb0d..17249c1 100755
Binary files a/out/main.wasm and b/out/main.wasm differ
diff --git a/out/market.wasm b/out/market.wasm
index 6d9c2ee..a31b2b2 100755
Binary files a/out/market.wasm and b/out/market.wasm differ
diff --git a/rust-toolchain b/rust-toolchain
index 47d5636..84c7d0b 100644
--- a/rust-toolchain
+++ b/rust-toolchain
@@ -1 +1 @@
-1.56.0
\ No newline at end of file
+1.61.0
\ No newline at end of file