diff --git a/Cargo.lock b/Cargo.lock
index 2c38d96c120e..679ee82a04d4 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -855,7 +855,7 @@ dependencies = [
  "hashmap_core 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "num-traits 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.6.4 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -907,7 +907,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 name = "fork-tree"
 version = "2.0.0"
 dependencies = [
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1218,7 +1218,7 @@ dependencies = [
 
 [[package]]
 name = "hyper"
-version = "0.12.31"
+version = "0.12.32"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "bytes 0.4.12 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1260,7 +1260,7 @@ name = "impl-codec"
 version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1337,7 +1337,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "failure 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.1.28 (registry+https://github.com/rust-lang/crates.io-index)",
- "hyper 0.12.31 (registry+https://github.com/rust-lang/crates.io-index)",
+ "hyper 0.12.32 (registry+https://github.com/rust-lang/crates.io-index)",
  "jsonrpc-core 12.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "jsonrpc-pubsub 12.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1383,7 +1383,7 @@ name = "jsonrpc-http-server"
 version = "12.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "hyper 0.12.31 (registry+https://github.com/rust-lang/crates.io-index)",
+ "hyper 0.12.32 (registry+https://github.com/rust-lang/crates.io-index)",
  "jsonrpc-core 12.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "jsonrpc-server-utils 12.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2194,7 +2194,7 @@ dependencies = [
  "node-executor 2.0.0",
  "node-primitives 2.0.0",
  "node-runtime 2.0.0",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-io 2.0.0",
  "sr-primitives 2.0.0",
@@ -2230,7 +2230,7 @@ version = "2.0.0"
 dependencies = [
  "node-primitives 2.0.0",
  "node-runtime 2.0.0",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-io 2.0.0",
  "sr-primitives 2.0.0",
  "srml-balances 2.0.0",
@@ -2257,7 +2257,7 @@ dependencies = [
 name = "node-primitives"
 version = "2.0.0"
 dependencies = [
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "pretty_assertions 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.94 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-primitives 2.0.0",
@@ -2272,7 +2272,7 @@ version = "2.0.0"
 dependencies = [
  "env_logger 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.1.28 (registry+https://github.com/rust-lang/crates.io-index)",
- "hyper 0.12.31 (registry+https://github.com/rust-lang/crates.io-index)",
+ "hyper 0.12.32 (registry+https://github.com/rust-lang/crates.io-index)",
  "jsonrpc-core-client 12.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "node-primitives 2.0.0",
@@ -2285,7 +2285,7 @@ version = "2.0.0"
 dependencies = [
  "integer-sqrt 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "node-primitives 2.0.0",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-hex 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "safe-mix 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.94 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2327,7 +2327,7 @@ dependencies = [
  "futures 0.1.28 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "node-template-runtime 2.0.0",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-io 2.0.0",
  "substrate-basic-authorship 2.0.0",
@@ -2349,7 +2349,7 @@ dependencies = [
 name = "node-template-runtime"
 version = "2.0.0"
 dependencies = [
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "safe-mix 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.94 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-io 2.0.0",
@@ -2503,7 +2503,7 @@ source = "git+https://github.com/paritytech/parity-common?rev=b0317f649ab2c665b7
 
 [[package]]
 name = "parity-codec"
-version = "4.1.1"
+version = "4.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "arrayvec 0.4.10 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3094,7 +3094,7 @@ dependencies = [
  "error-chain 0.12.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.1.28 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -3477,7 +3477,7 @@ version = "2.0.0"
 dependencies = [
  "blake2-rfc 0.2.18 (registry+https://github.com/rust-lang/crates.io-index)",
  "criterion 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "proc-macro-crate 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "proc-macro2 0.4.30 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3499,7 +3499,7 @@ dependencies = [
  "environmental 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "hash-db 0.14.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "libsecp256k1 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-std 2.0.0",
  "substrate-offchain 2.0.0",
@@ -3516,7 +3516,7 @@ dependencies = [
  "integer-sqrt 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "num-traits 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "paste 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "primitive-types 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.94 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3531,7 +3531,7 @@ name = "sr-sandbox"
 version = "2.0.0"
 dependencies = [
  "assert_matches 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-std 2.0.0",
  "substrate-primitives 2.0.0",
@@ -3551,7 +3551,7 @@ name = "sr-version"
 version = "2.0.0"
 dependencies = [
  "impl-serde 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.94 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-primitives 2.0.0",
  "sr-std 2.0.0",
@@ -3561,7 +3561,7 @@ dependencies = [
 name = "srml-assets"
 version = "2.0.0"
 dependencies = [
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.94 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-io 2.0.0",
  "sr-primitives 2.0.0",
@@ -3576,7 +3576,7 @@ name = "srml-aura"
 version = "2.0.0"
 dependencies = [
  "lazy_static 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.94 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-io 2.0.0",
@@ -3596,7 +3596,7 @@ dependencies = [
 name = "srml-authorship"
 version = "0.1.0"
 dependencies = [
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-io 2.0.0",
  "sr-primitives 2.0.0",
  "sr-std 2.0.0",
@@ -3611,7 +3611,7 @@ version = "2.0.0"
 dependencies = [
  "hex-literal 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.94 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-io 2.0.0",
@@ -3630,7 +3630,7 @@ dependencies = [
 name = "srml-balances"
 version = "2.0.0"
 dependencies = [
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "safe-mix 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.94 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-io 2.0.0",
@@ -3649,7 +3649,7 @@ dependencies = [
  "assert_matches 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "hex 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "hex-literal 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parity-wasm 0.31.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "pwasm-utils 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.94 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3671,7 +3671,7 @@ name = "srml-council"
 version = "2.0.0"
 dependencies = [
  "hex-literal 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "safe-mix 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.94 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-io 2.0.0",
@@ -3688,7 +3688,7 @@ dependencies = [
 name = "srml-democracy"
 version = "2.0.0"
 dependencies = [
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "safe-mix 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.94 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-io 2.0.0",
@@ -3704,7 +3704,7 @@ dependencies = [
 name = "srml-example"
 version = "2.0.0"
 dependencies = [
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.94 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-io 2.0.0",
  "sr-primitives 2.0.0",
@@ -3719,7 +3719,7 @@ name = "srml-executive"
 version = "2.0.0"
 dependencies = [
  "hex-literal 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.94 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-io 2.0.0",
  "sr-primitives 2.0.0",
@@ -3735,7 +3735,7 @@ dependencies = [
 name = "srml-finality-tracker"
 version = "2.0.0"
 dependencies = [
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.94 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-io 2.0.0",
  "sr-primitives 2.0.0",
@@ -3750,7 +3750,7 @@ dependencies = [
 name = "srml-grandpa"
 version = "2.0.0"
 dependencies = [
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.94 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-io 2.0.0",
  "sr-primitives 2.0.0",
@@ -3767,7 +3767,7 @@ dependencies = [
 name = "srml-indices"
 version = "2.0.0"
 dependencies = [
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "ref_thread_local 0.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "safe-mix 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.94 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3784,7 +3784,7 @@ dependencies = [
 name = "srml-metadata"
 version = "2.0.0"
 dependencies = [
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.94 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-std 2.0.0",
  "substrate-primitives 2.0.0",
@@ -3795,7 +3795,7 @@ name = "srml-session"
 version = "2.0.0"
 dependencies = [
  "lazy_static 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "safe-mix 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.94 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-io 2.0.0",
@@ -3812,7 +3812,7 @@ dependencies = [
 name = "srml-staking"
 version = "2.0.0"
 dependencies = [
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "safe-mix 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.94 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3832,7 +3832,7 @@ dependencies = [
 name = "srml-sudo"
 version = "2.0.0"
 dependencies = [
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.94 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-io 2.0.0",
  "sr-primitives 2.0.0",
@@ -3849,7 +3849,7 @@ version = "2.0.0"
 dependencies = [
  "bitmask 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "once_cell 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "paste 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "pretty_assertions 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.94 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3898,7 +3898,7 @@ dependencies = [
 name = "srml-support-test"
 version = "2.0.0"
 dependencies = [
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.94 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-io 2.0.0",
  "srml-support 2.0.0",
@@ -3912,7 +3912,7 @@ name = "srml-system"
 version = "2.0.0"
 dependencies = [
  "criterion 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "safe-mix 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.94 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-io 2.0.0",
@@ -3926,7 +3926,7 @@ dependencies = [
 name = "srml-timestamp"
 version = "2.0.0"
 dependencies = [
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.94 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-io 2.0.0",
  "sr-primitives 2.0.0",
@@ -3941,7 +3941,7 @@ dependencies = [
 name = "srml-treasury"
 version = "2.0.0"
 dependencies = [
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.94 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-io 2.0.0",
  "sr-primitives 2.0.0",
@@ -4033,7 +4033,7 @@ dependencies = [
  "hex-literal 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "node-primitives 2.0.0",
  "node-runtime 2.0.0",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-hex 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "schnorrkel 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -4058,7 +4058,7 @@ name = "substrate-basic-authorship"
 version = "2.0.0"
 dependencies = [
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-primitives 2.0.0",
  "substrate-client 2.0.0",
  "substrate-consensus-aura-primitives 2.0.0",
@@ -4127,7 +4127,7 @@ dependencies = [
  "kvdb 0.1.0 (git+https://github.com/paritytech/parity-common?rev=b0317f649ab2c665b7987b8475878fc4d2e1f81d)",
  "kvdb-memorydb 0.1.0 (git+https://github.com/paritytech/parity-common?rev=b0317f649ab2c665b7987b8475878fc4d2e1f81d)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-api-macros 2.0.0",
  "sr-primitives 2.0.0",
@@ -4155,7 +4155,7 @@ dependencies = [
  "kvdb-rocksdb 0.1.4 (git+https://github.com/paritytech/parity-common?rev=b0317f649ab2c665b7987b8475878fc4d2e1f81d)",
  "linked-hash-map 0.5.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-primitives 2.0.0",
  "substrate-client 2.0.0",
@@ -4176,7 +4176,7 @@ dependencies = [
  "env_logger 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.1.28 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-io 2.0.0",
  "sr-primitives 2.0.0",
@@ -4203,7 +4203,7 @@ dependencies = [
 name = "substrate-consensus-aura-primitives"
 version = "2.0.0"
 dependencies = [
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-primitives 2.0.0",
  "sr-std 2.0.0",
  "substrate-client 2.0.0",
@@ -4218,7 +4218,7 @@ dependencies = [
  "futures 0.1.28 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "merlin 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "schnorrkel 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -4247,7 +4247,7 @@ dependencies = [
 name = "substrate-consensus-babe-primitives"
 version = "2.0.0"
 dependencies = [
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-primitives 2.0.0",
  "sr-std 2.0.0",
  "substrate-client 2.0.0",
@@ -4263,7 +4263,7 @@ dependencies = [
  "futures 0.1.28 (registry+https://github.com/rust-lang/crates.io-index)",
  "libp2p 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-primitives 2.0.0",
  "sr-std 2.0.0",
@@ -4283,7 +4283,7 @@ dependencies = [
  "exit-future 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.1.28 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rhododendron 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-io 2.0.0",
@@ -4305,7 +4305,7 @@ version = "2.0.0"
 dependencies = [
  "futures 0.1.28 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-primitives 2.0.0",
  "substrate-client 2.0.0",
@@ -4327,7 +4327,7 @@ dependencies = [
  "lazy_static 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "libsecp256k1 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-io 2.0.0",
  "sr-version 2.0.0",
@@ -4353,7 +4353,7 @@ dependencies = [
  "fork-tree 2.0.0",
  "futures 0.1.28 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_json 1.0.40 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -4378,7 +4378,7 @@ dependencies = [
 name = "substrate-finality-grandpa-primitives"
 version = "2.0.0"
 dependencies = [
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.94 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-primitives 2.0.0",
  "sr-std 2.0.0",
@@ -4390,7 +4390,7 @@ dependencies = [
 name = "substrate-inherents"
 version = "2.0.0"
 dependencies = [
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-primitives 2.0.0",
  "sr-std 2.0.0",
@@ -4437,7 +4437,7 @@ dependencies = [
  "linked_hash_set 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "lru-cache 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "quickcheck 0.8.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -4472,7 +4472,7 @@ dependencies = [
  "env_logger 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.1.28 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-primitives 2.0.0",
  "substrate-client 2.0.0",
@@ -4529,7 +4529,7 @@ dependencies = [
  "hex-literal 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "impl-serde 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "num-traits 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "pretty_assertions 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "primitive-types 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -4559,7 +4559,7 @@ dependencies = [
  "jsonrpc-derive 12.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "jsonrpc-pubsub 12.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-hex 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.94 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -4621,7 +4621,7 @@ dependencies = [
  "node-executor 2.0.0",
  "node-primitives 2.0.0",
  "node-runtime 2.0.0",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.94 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_json 1.0.40 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -4671,7 +4671,7 @@ version = "2.0.0"
 dependencies = [
  "env_logger 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "substrate-primitives 2.0.0",
 ]
@@ -4684,7 +4684,7 @@ dependencies = [
  "hex-literal 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "num-traits 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "substrate-panic-handler 2.0.0",
  "substrate-primitives 2.0.0",
@@ -4719,7 +4719,7 @@ version = "2.0.0"
 dependencies = [
  "futures 0.1.28 (registry+https://github.com/rust-lang/crates.io-index)",
  "hash-db 0.14.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-primitives 2.0.0",
  "substrate-client 2.0.0",
  "substrate-client-db 2.0.0",
@@ -4736,7 +4736,7 @@ version = "2.0.0"
 dependencies = [
  "cfg-if 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.94 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-io 2.0.0",
  "sr-primitives 2.0.0",
@@ -4777,7 +4777,7 @@ dependencies = [
  "env_logger 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.1.28 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.94 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-primitives 2.0.0",
@@ -4792,7 +4792,7 @@ dependencies = [
  "derive_more 0.14.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.1.28 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-primitives 2.0.0",
  "substrate-client 2.0.0",
@@ -4811,7 +4811,7 @@ dependencies = [
  "hex-literal 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "keccak-hasher 0.14.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "memory-db 0.14.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-std 2.0.0",
  "substrate-primitives 2.0.0",
  "trie-bench 0.14.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -5229,7 +5229,7 @@ name = "transaction-factory"
 version = "0.0.1"
 dependencies = [
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "sr-primitives 2.0.0",
  "substrate-cli 2.0.0",
  "substrate-client 2.0.0",
@@ -5247,7 +5247,7 @@ dependencies = [
  "hash-db 0.14.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "keccak-hasher 0.14.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "memory-db 0.14.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "trie-db 0.14.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "trie-root 0.14.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "trie-standardmap 0.14.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -5932,7 +5932,7 @@ dependencies = [
 "checksum httparse 1.3.4 (registry+https://github.com/rust-lang/crates.io-index)" = "cd179ae861f0c2e53da70d892f5f3029f9594be0c41dc5269cd371691b1dc2f9"
 "checksum humantime 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "3ca7e5f2e110db35f93b837c81797f3714500b81d517bf20c431b16d3ca4f114"
 "checksum hyper 0.10.16 (registry+https://github.com/rust-lang/crates.io-index)" = "0a0652d9a2609a968c14be1a9ea00bf4b1d64e2e1f53a1b51b6fff3a6e829273"
-"checksum hyper 0.12.31 (registry+https://github.com/rust-lang/crates.io-index)" = "6481fff8269772d4463253ca83c788104a7305cb3fb9136bc651a6211e46e03f"
+"checksum hyper 0.12.32 (registry+https://github.com/rust-lang/crates.io-index)" = "a64d71c1e77d39da024f06f5821ee00ad9c38febb90370bad1f07a94e0bc8793"
 "checksum idna 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "38f09e0f0b1fb55fdee1f17470ad800da77af5186a1a76c026b679358b7e844e"
 "checksum impl-codec 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "62ed8ff267bc916dd848a800b96d3129aec73d5b23a5e3d018c83655d0c55371"
 "checksum impl-serde 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "5158079de9d4158e0ce1de3ae0bd7be03904efc40b3d7dd8b8c301cbf6b52b56"
@@ -6031,7 +6031,7 @@ dependencies = [
 "checksum owning_ref 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "cdf84f41639e037b484f93433aa3897863b561ed65c6e59c7073d7c561710f37"
 "checksum owning_ref 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "49a4b8ea2179e6a2e27411d3bca09ca6dd630821cf6894c6c7c8467a8ee7ef13"
 "checksum parity-bytes 0.1.0 (git+https://github.com/paritytech/parity-common?rev=b0317f649ab2c665b7987b8475878fc4d2e1f81d)" = "<none>"
-"checksum parity-codec 4.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "7902deb39d3b431897f211c1918789938251e67a740f55effd53201e79c0906c"
+"checksum parity-codec 4.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "245e685a5c12ee06d523d63acce60c522dd0986dbf20b971cf55ede54d35e104"
 "checksum parity-codec-derive 3.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "00a486fd383382ddcb2de928364b1f82571c1e48274fc43b7667a4738ee4056c"
 "checksum parity-multiaddr 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "045b3c7af871285146300da35b1932bb6e4639b66c7c98e85d06a32cbc4e8fa7"
 "checksum parity-multihash 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "eb83358a0c05e52c44d658981fec2d146d3516d1adffd9e553684f8c8e9e8fa5"
diff --git a/core/finality-grandpa/src/aux_schema.rs b/core/finality-grandpa/src/aux_schema.rs
index f3939f465027..59175e1f5b43 100644
--- a/core/finality-grandpa/src/aux_schema.rs
+++ b/core/finality-grandpa/src/aux_schema.rs
@@ -18,6 +18,9 @@
 
 use std::fmt::Debug;
 use std::sync::Arc;
+use std::collections::VecDeque;
+use std::iter::FromIterator;
+
 use parity_codec::{Encode, Decode};
 use client::backend::AuxStore;
 use client::error::{Result as ClientResult, Error as ClientError};
@@ -30,15 +33,73 @@ use fg_primitives::AuthorityId;
 
 use crate::authorities::{AuthoritySet, SharedAuthoritySet, PendingChange, DelayKind};
 use crate::consensus_changes::{SharedConsensusChanges, ConsensusChanges};
-use crate::environment::{CompletedRound, CompletedRounds, HasVoted, SharedVoterSetState, VoterSetState};
-use crate::NewAuthoritySet;
+use crate::environment::{
+	CompletedRound, CompletedRounds, HasVoted, SharedVoterSetState, VoterSetState,
+};
+use crate::{NewAuthoritySet, HistoricalVotes, SignedMessage};
 
 const VERSION_KEY: &[u8] = b"grandpa_schema_version";
 const SET_STATE_KEY: &[u8] = b"grandpa_completed_round";
 const AUTHORITY_SET_KEY: &[u8] = b"grandpa_voters";
 const CONSENSUS_CHANGES_KEY: &[u8] = b"grandpa_consensus_changes";
 
-const CURRENT_VERSION: u32 = 2;
+const CURRENT_VERSION: u32 = 3;
+
+/// Data about a completed round.
+#[derive(Debug, Clone, Decode, Encode, PartialEq)]
+pub struct V2CompletedRound<Block: BlockT> {
+	/// The round number.
+	pub number: u64,
+	/// The round state (prevote ghost, estimate, finalized, etc.)
+	pub state: RoundState<Block::Hash, NumberFor<Block>>,
+	/// The target block base used for voting in the round.
+	pub base: (Block::Hash, NumberFor<Block>),
+	/// All the votes observed in the round.
+	pub votes: Vec<SignedMessage<Block>>,
+}
+
+// Data about last completed rounds.
+#[derive(Debug, Clone, PartialEq)]
+pub struct V2CompletedRounds<Block: BlockT> {
+	rounds: VecDeque<V2CompletedRound<Block>>,
+	set_id: u64,
+	voters: Vec<AuthorityId>,
+}
+
+impl<Block: BlockT> Encode for V2CompletedRounds<Block> {
+	fn encode(&self) -> Vec<u8> {
+		let v = Vec::from_iter(&self.rounds);
+		(&v, &self.set_id, &self.voters).encode()
+	}
+}
+
+impl<Block: BlockT> Decode for V2CompletedRounds<Block> {
+	fn decode<I: parity_codec::Input>(value: &mut I) -> Option<Self> {
+		<(Vec<V2CompletedRound<Block>>, u64, Vec<AuthorityId>)>::decode(value)
+			.map(|(rounds, set_id, voters)| V2CompletedRounds {
+				rounds: rounds.into(),
+				set_id,
+				voters,
+			})
+	}
+}
+
+// The state of the current voter set.
+#[derive(Debug, Decode, Encode, PartialEq)]
+pub enum V2VoterSetState<Block: BlockT> {
+	/// The voter is live, i.e. participating in rounds.
+	Live {
+		/// The previously completed rounds.
+		completed_rounds: V2CompletedRounds<Block>,
+		/// Vote status for the current round.
+		current_round: HasVoted<Block>,
+	},
+	/// The voter is paused, i.e. not casting or importing any votes.
+	Paused {
+		/// The previously completed rounds.
+		completed_rounds: V2CompletedRounds<Block>,
+	},
+}
 
 /// The voter set state.
 #[derive(Debug, Clone, Encode, Decode)]
@@ -155,16 +216,21 @@ fn migrate_from_version0<Block: BlockT, B, G>(
 		let base = last_round_state.prevote_ghost
 			.expect("state is for completed round; completed rounds must have a prevote ghost; qed.");
 
+		let completed_round = CompletedRound {
+			number: last_round_number,
+			state: last_round_state,
+			base,
+			historical_votes: HistoricalVotes::<Block>::new(),
+		};
+		let mut rounds = VecDeque::new();
+		rounds.push_back(completed_round);
+		let voters = new_set.current().1.iter().map(|(a, _)| a.clone()).collect();
+		
 		let set_state = VoterSetState::Live {
 			completed_rounds: CompletedRounds::new(
-				CompletedRound {
-					number: last_round_number,
-					state: last_round_state,
-					votes: Vec::new(),
-					base,
-				},
+				rounds,
 				set_id,
-				&new_set,
+				voters,
 			),
 			current_round: HasVoted::No,
 		};
@@ -195,17 +261,23 @@ fn migrate_from_version1<Block: BlockT, B, G>(
 		AUTHORITY_SET_KEY,
 	)? {
 		let set_id = set.current().0;
-
-		let completed_rounds = |number, state, base| CompletedRounds::new(
-			CompletedRound {
+		let completed_rounds = |number, state, base| {
+			let completed_round = CompletedRound {
 				number,
 				state,
-				votes: Vec::new(),
 				base,
-			},
-			set_id,
-			&set,
-		);
+				historical_votes: HistoricalVotes::<Block>::new(),
+			};
+			let mut rounds = VecDeque::new();
+			rounds.push_back(completed_round);
+			let voters = set.current().1.iter().map(|(a, _)| a.clone()).collect();
+		
+			CompletedRounds::new(
+				rounds,
+				set_id,
+				voters,
+			)
+		};
 
 		let set_state = match load_decode::<_, V1VoterSetState<Block::Hash, NumberFor<Block>>>(
 			backend,
@@ -248,6 +320,98 @@ fn migrate_from_version1<Block: BlockT, B, G>(
 	Ok(None)
 }
 
+fn voter_set_state_from_v2<Block: BlockT>(voter_set_state_v2: V2VoterSetState<Block>) -> VoterSetState<Block> {
+	let transform = |completed_rounds: V2CompletedRounds<Block>| {
+		CompletedRounds::new(
+			completed_rounds.rounds.into_iter().map(
+				| V2CompletedRound { number, state, base, votes } | {
+					CompletedRound {
+						number,
+						state,
+						base,
+						historical_votes: HistoricalVotes::<Block>::new_with(votes, None, None),
+					}
+				}
+			).collect::<VecDeque<CompletedRound<Block>>>(),
+			completed_rounds.set_id,
+			completed_rounds.voters,
+		)
+	};
+	match voter_set_state_v2 {
+		V2VoterSetState::Paused { completed_rounds } => {
+			VoterSetState::Paused {
+				completed_rounds: transform(completed_rounds)
+			}
+		},
+		V2VoterSetState::Live { completed_rounds, current_round } => {
+			VoterSetState::Live {
+				completed_rounds: transform(completed_rounds),
+				current_round,
+			}
+		},
+	}
+}
+
+fn migrate_from_version2<Block: BlockT, B, G>(
+	backend: &B,
+	genesis_round: &G,
+) -> ClientResult<Option<(
+	AuthoritySet<Block::Hash, NumberFor<Block>>,
+	VoterSetState<Block>,
+)>> where B: AuxStore,
+		  G: Fn() -> RoundState<Block::Hash, NumberFor<Block>>,
+{
+	CURRENT_VERSION.using_encoded(|s|
+		backend.insert_aux(&[(VERSION_KEY, s)], &[])
+	)?;
+
+	if let Some(set) = load_decode::<_, AuthoritySet<Block::Hash, NumberFor<Block>>>(
+		backend,
+		AUTHORITY_SET_KEY,
+	)? {
+		let set_state = match load_decode::<_, V2VoterSetState<Block>>(
+			backend,
+			SET_STATE_KEY,
+		)? {
+			Some(voter_set_state_v2) => voter_set_state_from_v2(voter_set_state_v2),
+			None => {
+				let completed_rounds = |number, state, base| {
+					let completed_round = CompletedRound {
+						number,
+						state,
+						base,
+						historical_votes: HistoricalVotes::<Block>::new(),
+					};
+					let mut rounds = VecDeque::new();
+					rounds.push_back(completed_round);
+					let voters = set.current().1.iter().map(|(a, _)| a.clone()).collect();
+
+					CompletedRounds::new(
+						rounds,
+						set.current().0,
+						voters,
+					)
+				};
+
+				let set_state = genesis_round();
+				let base = set_state.prevote_ghost
+					.expect("state is for completed round; completed rounds must have a prevote ghost; qed.");
+
+				VoterSetState::Live {
+					completed_rounds: completed_rounds(0, set_state, base),
+					current_round: HasVoted::No,
+				}
+			},
+		};
+
+		backend.insert_aux(&[(SET_STATE_KEY, set_state.encode().as_slice())], &[])?;
+
+		return Ok(Some((set, set_state)));
+	}
+
+	Ok(None)
+}
+
 /// Load or initialize persistent data from backend.
 pub(crate) fn load_persistent<Block: BlockT, B, G>(
 	backend: &B,
@@ -286,6 +450,15 @@ pub(crate) fn load_persistent<Block: BlockT, B, G>(
 			}
 		},
 		Some(2) => {
+			if let Some((new_set, set_state)) = migrate_from_version2::<Block, _, _>(backend, &make_genesis_round)? {
+				return Ok(PersistentData {
+					authority_set: new_set.into(),
+					consensus_changes: Arc::new(consensus_changes.into()),
+					set_state: set_state.into(),
+				});
+			}
+		},
+		Some(3) => {
 			if let Some(set) = load_decode::<_, AuthoritySet<Block::Hash, NumberFor<Block>>>(
 				backend,
 				AUTHORITY_SET_KEY,
@@ -300,16 +473,22 @@ pub(crate) fn load_persistent<Block: BlockT, B, G>(
 						let base = state.prevote_ghost
 							.expect("state is for completed round; completed rounds must have a prevote ghost; qed.");
 
+						let completed_round = CompletedRound {
+							number: 0,
+							historical_votes: HistoricalVotes::<Block>::new(),
+							base,
+							state,
+						};
+						let mut rounds = VecDeque::new();
+						rounds.push_back(completed_round);
+						let voters = set
+							.current().1.iter().map(|(a, _)| a.clone()).collect();
+		
 						VoterSetState::Live {
 							completed_rounds: CompletedRounds::new(
-								CompletedRound {
-									number: 0,
-									votes: Vec::new(),
-									base,
-									state,
-								},
+								rounds,
 								set.current().0,
-								&set,
+								voters,
 							),
 							current_round: HasVoted::No,
 						}
@@ -338,16 +517,22 @@ pub(crate) fn load_persistent<Block: BlockT, B, G>(
 	let base = state.prevote_ghost
 		.expect("state is for completed round; completed rounds must have a prevote ghost; qed.");
 
+	let completed_round = CompletedRound {
+		number: 0,
+		state,
+		base,
+		historical_votes: HistoricalVotes::<Block>::new(),
+	};
+
+	let mut rounds = VecDeque::new();
+	rounds.push_back(completed_round);
+	let voters = genesis_set.current().1.iter().map(|(a, _)| a.clone()).collect();
+		
 	let genesis_state = VoterSetState::Live {
 		completed_rounds: CompletedRounds::new(
-			CompletedRound {
-				number: 0,
-				votes: Vec::new(),
-				state,
-				base,
-			},
+			rounds,
 			0,
-			&genesis_set,
+			voters,
 		),
 		current_round: HasVoted::No,
 	};
@@ -400,16 +585,21 @@ pub(crate) fn update_authority_set<Block: BlockT, F, R>(
 			new_set.canon_hash.clone(),
 			new_set.canon_number.clone(),
 		));
+		let completed_round = CompletedRound {
+			number: 0,
+			state: round_state,
+			historical_votes: HistoricalVotes::<Block>::new(),
+			base: (new_set.canon_hash, new_set.canon_number),
+		};
+		let mut rounds = VecDeque::new();
+		rounds.push_back(completed_round);
+		let voters = set.current().1.iter().map(|(a, _)| a.clone()).collect();
+		
 		let set_state = VoterSetState::<Block>::Live {
 			completed_rounds: CompletedRounds::new(
-				CompletedRound {
-					number: 0,
-					state: round_state,
-					votes: Vec::new(),
-					base: (new_set.canon_hash, new_set.canon_number),
-				},
+				rounds,
 				new_set.set_id,
-				&set,
+				voters,
 			),
 			current_round: HasVoted::No,
 		};
@@ -458,6 +648,9 @@ pub(crate) fn load_authorities<B: AuxStore, H: Decode, N: Decode>(backend: &B)
 mod test {
 	use substrate_primitives::H256;
 	use test_client;
+	use test_client::runtime::Block;
+	use crate::Prevote;
+	use crate::environment::Vote;
 	use super::*;
 
 	#[test]
@@ -507,10 +700,10 @@ mod test {
 
 		assert_eq!(
 			load_decode::<_, u32>(&client, VERSION_KEY).unwrap(),
-			Some(2),
+			Some(3),
 		);
 
-		let PersistentData { authority_set, set_state, .. } = load_persistent::<test_client::runtime::Block, _, _>(
+		let PersistentData { authority_set, set_state, .. } = load_persistent::<Block, _, _>(
 			&client,
 			H256::random(),
 			0,
@@ -527,18 +720,24 @@ mod test {
 			},
 		);
 
+		let completed_round = CompletedRound {
+			number: round_number,
+			state: round_state.clone(),
+			base: round_state.prevote_ghost.unwrap(),
+			historical_votes: HistoricalVotes::<Block>::new(),
+		};
+		let mut rounds = VecDeque::new();
+		rounds.push_back(completed_round);
+		let voters = authority_set.inner().read()
+			.current().1.iter().map(|(a, _)| a.clone()).collect();
+		
 		assert_eq!(
 			&*set_state.read(),
 			&VoterSetState::Live {
 				completed_rounds: CompletedRounds::new(
-					CompletedRound {
-						number: round_number,
-						state: round_state.clone(),
-						base: round_state.prevote_ghost.unwrap(),
-						votes: vec![],
-					},
+					rounds,
 					set_id,
-					&*authority_set.inner().read(),
+					voters,
 				),
 				current_round: HasVoted::No,
 			},
@@ -592,12 +791,118 @@ mod test {
 			|| unreachable!(),
 		).unwrap();
 
+		assert_eq!(
+			load_decode::<_, u32>(&client, VERSION_KEY).unwrap(),
+			Some(3),
+		);
+
+		let PersistentData { authority_set, set_state, .. } =
+			load_persistent::<test_client::runtime::Block, _, _>(
+				&client,
+				H256::random(),
+				0,
+				|| unreachable!(),
+			).unwrap();
+
+		assert_eq!(
+			*authority_set.inner().read(),
+			AuthoritySet {
+				current_authorities: authorities.clone(),
+				pending_standard_changes: ForkTree::new(),
+				pending_forced_changes: Vec::new(),
+				set_id,
+			},
+		);
+
+		let completed_round = CompletedRound {
+			number: round_number,
+			state: round_state.clone(),
+			base: round_state.prevote_ghost.unwrap(),
+			historical_votes: HistoricalVotes::<Block>::new(),
+		};
+
+		let mut rounds = VecDeque::new();
+		rounds.push_back(completed_round);
+		let voters = authority_set.inner().read()
+			.current().1.iter().map(|(a, _)| a.clone()).collect();
+
+		assert_eq!(
+			&*set_state.read(),
+			&VoterSetState::Live {
+				completed_rounds: CompletedRounds::new(
+					rounds,
+					set_id,
+					voters,
+				),
+				current_round: HasVoted::No,
+			},
+		);
+	}
+
+	#[test]
+	fn load_decode_from_v2_migrates_data_format() {
+		let client = test_client::new();
+		let voters = vec![AuthorityId::default()];
+		let authorities = vec![(AuthorityId::default(), 100)];
+		let set_id = 3;
+		let h = H256::random();
+		let n = 32;
+
+		let prevote = Prevote::<Block>::new(h.clone(), n.clone());
+		let vote = Vote::Prevote(None, prevote);
+
+		{
+			let current_round = HasVoted::Yes(AuthorityId::default(), vote.clone());
+
+			let authority_set = AuthoritySet::<H256, u64> {
+				current_authorities: authorities.clone(),
+				pending_standard_changes: ForkTree::new(),
+				pending_forced_changes: Vec::new(),
+				set_id,
+			};
+
+			let rounds = VecDeque::new();
+
+			let completed_rounds = V2CompletedRounds {
+				rounds,
+				set_id,
+				voters,
+			};
+
+			let voter_set_state = V2VoterSetState::Live {
+				completed_rounds,
+				current_round,
+			};
+
+			client.insert_aux(
+				&[
+					(AUTHORITY_SET_KEY, authority_set.encode().as_slice()),
+					(SET_STATE_KEY, voter_set_state.encode().as_slice()),
+					(VERSION_KEY, 2u32.encode().as_slice()),
+				],
+				&[],
+			).unwrap();
+		}
+
 		assert_eq!(
 			load_decode::<_, u32>(&client, VERSION_KEY).unwrap(),
 			Some(2),
 		);
 
-		let PersistentData { authority_set, set_state, .. } = load_persistent::<test_client::runtime::Block, _, _>(
+		// should perform the migration
+		load_persistent::<Block, _, _>(
+			&client,
+			H256::random(),
+			0,
+			|| unreachable!(),
+		).unwrap();
+
+		assert_eq!(
+			load_decode::<_, u32>(&client, VERSION_KEY).unwrap(),
+			Some(3),
+		);
+
+		let PersistentData { authority_set, set_state, .. } = load_persistent::<Block, _, _>(
 			&client,
 			H256::random(),
 			0,
@@ -607,27 +912,26 @@ mod test {
 		assert_eq!(
 			*authority_set.inner().read(),
 			AuthoritySet {
-				current_authorities: authorities.clone(),
+				current_authorities: authorities,
 				pending_standard_changes: ForkTree::new(),
 				pending_forced_changes: Vec::new(),
 				set_id,
 			},
 		);
 
+		let rounds = VecDeque::new();
+		let voters = authority_set.inner().read()
+			.current().1.iter().map(|(a, _)| a.clone()).collect();
+
 		assert_eq!(
 			&*set_state.read(),
 			&VoterSetState::Live {
 				completed_rounds: CompletedRounds::new(
-					CompletedRound {
-						number: round_number,
-						state: round_state.clone(),
-						base: round_state.prevote_ghost.unwrap(),
-						votes: vec![],
-					},
+					rounds, 
 					set_id,
-					&*authority_set.inner().read(),
+					voters,
 				),
-				current_round: HasVoted::No,
+				current_round: HasVoted::Yes(AuthorityId::default(), vote),
 			},
 		);
 	}
diff --git a/core/finality-grandpa/src/communication/gossip.rs b/core/finality-grandpa/src/communication/gossip.rs
index dfaa96628f2d..803aa7c268ba 100644
--- a/core/finality-grandpa/src/communication/gossip.rs
+++ b/core/finality-grandpa/src/communication/gossip.rs
@@ -763,7 +763,7 @@ impl<Block: BlockT> Inner<Block> {
 		// code below assumes this invariant is maintained when creating the
 		// catch up reply since peers won't accept catch-up messages that have
 		// too many equivocations (we exceed the fault-tolerance bound).
-		for vote in last_completed_round.votes {
+		for vote in last_completed_round.historical_votes.seen().clone() {
 			match vote.message {
 				grandpa::Message::Prevote(prevote) => {
 					prevotes.push(grandpa::SignedPrevote {
@@ -1231,6 +1231,7 @@ impl<B: BlockT, N: super::Network<B>> Future for ReportingTask<B, N> {
 mod tests {
 	use super::*;
 	use super::environment::SharedVoterSetState;
+	use crate::HistoricalVotes;
 	use network_gossip::Validator as GossipValidatorT;
 	use network::test::Block;
 
@@ -1246,24 +1247,27 @@ mod tests {
 
 	// dummy voter set state
 	fn voter_set_state() -> SharedVoterSetState<Block> {
-		use crate::authorities::AuthoritySet;
 		use crate::environment::{CompletedRound, CompletedRounds, HasVoted, VoterSetState};
 		use grandpa::round::State as RoundState;
 		use substrate_primitives::H256;
 
 		let state = RoundState::genesis((H256::zero(), 0));
 		let base = state.prevote_ghost.unwrap();
-		let voters = AuthoritySet::genesis(Vec::new());
+		let voters = Vec::new();
+		let completed_round = CompletedRound {
+			state,
+			number: 0,
+			base,
+			historical_votes: HistoricalVotes::<Block>::new(),
+		};
+		let mut rounds = VecDeque::new();
+		rounds.push_back(completed_round);
+
 		let set_state = VoterSetState::Live {
 			completed_rounds: CompletedRounds::new(
-				CompletedRound {
-					state,
-					number: 0,
-					votes: Vec::new(),
-					base,
-				},
+				rounds,
 				0,
-				&voters,
+				voters,
 			),
 			current_round: HasVoted::No,
 		};
@@ -1545,7 +1549,7 @@ mod tests {
 				number: 1,
 				state: grandpa::round::State::genesis(Default::default()),
 				base: Default::default(),
-				votes: Default::default(),
+				historical_votes: HistoricalVotes::<Block>::new(),
 			}));
 
 			let set_state = environment::VoterSetState::<Block>::Live {
diff --git a/core/finality-grandpa/src/communication/mod.rs b/core/finality-grandpa/src/communication/mod.rs
index 4707dede78d6..58e327a44857 100644
--- a/core/finality-grandpa/src/communication/mod.rs
+++ b/core/finality-grandpa/src/communication/mod.rs
@@ -265,7 +265,7 @@ impl<B: BlockT, N: Network<B>> NetworkBridge<B, N> {
 				// messages will be ignored.
 				validator.note_round(Round(round.number), |_, _| {});
 
-				for signed in round.votes.iter() {
+				for signed in round.historical_votes.seen().iter() {
 					let message = gossip::GossipMessage::VoteOrPrecommit(
 						gossip::VoteOrPrecommitMessage::<B> {
 							message: signed.clone(),
@@ -282,7 +282,7 @@ impl<B: BlockT, N: Network<B>> NetworkBridge<B, N> {
 
 				trace!(target: "afg",
 					"Registered {} messages for topic {:?} (round: {}, set_id: {})",
-					round.votes.len(),
+					round.historical_votes.seen().len(),
 					topic,
 					round.number,
 					set_id,
diff --git a/core/finality-grandpa/src/communication/tests.rs b/core/finality-grandpa/src/communication/tests.rs
index 5760b3936cd9..f71af8f1d5a2 100644
--- a/core/finality-grandpa/src/communication/tests.rs
+++ b/core/finality-grandpa/src/communication/tests.rs
@@ -23,10 +23,12 @@ use network::test::{Block, Hash};
 use network_gossip::Validator;
 use tokio::runtime::current_thread;
 use std::sync::Arc;
+use std::collections::VecDeque;
 use keyring::AuthorityKeyring;
 use parity_codec::Encode;
 
 use crate::environment::SharedVoterSetState;
+use crate::HistoricalVotes;
 use super::gossip::{self, GossipValidator};
 use super::{AuthorityId, VoterSet, Round, SetId};
 
@@ -140,24 +142,26 @@ fn config() -> crate::Config {
 
 // dummy voter set state
 fn voter_set_state() -> SharedVoterSetState<Block> {
-	use crate::authorities::AuthoritySet;
 	use crate::environment::{CompletedRound, CompletedRounds, HasVoted, VoterSetState};
 	use grandpa::round::State as RoundState;
 	use substrate_primitives::H256;
 
 	let state = RoundState::genesis((H256::zero(), 0));
 	let base = state.prevote_ghost.unwrap();
-	let voters = AuthoritySet::genesis(Vec::new());
+	let voters = Vec::new();
+	let completed_round = CompletedRound {
+		state,
+		number: 0,
+		base,
+		historical_votes: HistoricalVotes::<Block>::new(),
+	};
+	let mut rounds = VecDeque::new();
+	rounds.push_back(completed_round);
 	let set_state = VoterSetState::Live {
 		completed_rounds: CompletedRounds::new(
-			CompletedRound {
-				state,
-				number: 0,
-				votes: Vec::new(),
-				base,
-			},
+			rounds,
 			0,
-			&voters,
+			voters,
 		),
 		current_round: HasVoted::No,
 	};
diff --git a/core/finality-grandpa/src/environment.rs b/core/finality-grandpa/src/environment.rs
index 414e3ca0ab43..67b698a4de4b 100644
--- a/core/finality-grandpa/src/environment.rs
+++ b/core/finality-grandpa/src/environment.rs
@@ -41,12 +41,12 @@ use substrate_telemetry::{telemetry, CONSENSUS_INFO};
 
 use crate::{
 	CommandOrError, Commit, Config, Error, Network, Precommit, Prevote,
-	PrimaryPropose, SignedMessage, NewAuthoritySet, VoterCommand,
+	PrimaryPropose, NewAuthoritySet, VoterCommand,
 };
 
 use consensus_common::SelectChain;
 
-use crate::authorities::{AuthoritySet, SharedAuthoritySet};
+use crate::authorities::SharedAuthoritySet;
 use crate::consensus_changes::SharedConsensusChanges;
 use crate::justification::GrandpaJustification;
 use crate::until_imported::UntilVoteTargetImported;
@@ -70,7 +70,7 @@ pub struct CompletedRound<Block: BlockT> {
 	/// The target block base used for voting in the round.
 	pub base: (Block::Hash, NumberFor<Block>),
 	/// All the votes observed in the round.
-	pub votes: Vec<SignedMessage<Block>>,
+	pub historical_votes: HistoricalVotes<Block>,
 }
 
 // Data about last completed rounds within a single voter set. Stores NUM_LAST_COMPLETED_ROUNDS and always
@@ -82,6 +82,7 @@ pub struct CompletedRounds<Block: BlockT> {
 	voters: Vec<AuthorityId>,
 }
 
+
 // NOTE: the current strategy for persisting completed rounds is very naive
 // (update everything) and we also rely on cloning to do atomic updates,
 // therefore this value should be kept small for now.
@@ -108,16 +109,12 @@ impl<Block: BlockT> Decode for CompletedRounds<Block> {
 impl<Block: BlockT> CompletedRounds<Block> {
 	/// Create a new completed rounds tracker with NUM_LAST_COMPLETED_ROUNDS capacity.
 	pub(crate) fn new(
-		genesis: CompletedRound<Block>,
+		rounds: VecDeque<CompletedRound<Block>>,
 		set_id: u64,
-		voters: &AuthoritySet<Block::Hash, NumberFor<Block>>,
+		voters: Vec<AuthorityId>,
 	)
 		-> CompletedRounds<Block>
 	{
-		let mut rounds = VecDeque::with_capacity(NUM_LAST_COMPLETED_ROUNDS);
-		rounds.push_back(genesis);
-
-		let voters = voters.current().1.iter().map(|(a, _)| a.clone()).collect();
 		CompletedRounds { rounds, set_id, voters }
 	}
 
@@ -668,15 +665,12 @@ where
 		self.update_voter_set_state(|voter_set_state| {
 			let mut completed_rounds = voter_set_state.completed_rounds();
 
-			// TODO: Future integration will store the prevote and precommit index. See #2611.
-			let votes = historical_votes.seen().clone();
-
 			// NOTE: the Environment assumes that rounds are *always* completed in-order.
 			if !completed_rounds.push(CompletedRound {
 				number: round,
 				state: state.clone(),
 				base,
-				votes,
+				historical_votes: historical_votes.clone(),
 			}) {
 				let msg = "Voter completed round that is older than the last completed round.";
 				return Err(Error::Safety(msg.to_string()));
diff --git a/core/finality-grandpa/src/lib.rs b/core/finality-grandpa/src/lib.rs
index 534a5d925603..cbed2b5e7eb4 100644
--- a/core/finality-grandpa/src/lib.rs
+++ b/core/finality-grandpa/src/lib.rs
@@ -77,6 +77,7 @@ use grandpa::{voter, round::State as RoundState, BlockNumberOps, voter_set::Vote
 use std::fmt;
 use std::sync::Arc;
 use std::time::Duration;
+use std::collections::VecDeque;
 
 mod authorities;
 mod aux_schema;
@@ -115,6 +116,7 @@ mod tests;
 
 /// A GRANDPA message for a substrate chain.
 pub type Message<Block> = grandpa::Message<<Block as BlockT>::Hash, NumberFor<Block>>;
+
 /// A signed message.
 pub type SignedMessage<Block> = grandpa::SignedMessage<
 	<Block as BlockT>::Hash,
@@ -123,12 +125,23 @@ pub type SignedMessage<Block> = grandpa::SignedMessage<
 	AuthorityId,
 >;
 
+/// An ordered set of historical votes.
+pub type HistoricalVotes<Block> = grandpa::HistoricalVotes<
+	<Block as BlockT>::Hash,
+	NumberFor<Block>,
+	AuthoritySignature,
+	AuthorityId,
+>;
+
 /// A primary propose message for this chain's block type.
 pub type PrimaryPropose<Block> = grandpa::PrimaryPropose<<Block as BlockT>::Hash, NumberFor<Block>>;
+
 /// A prevote message for this chain's block type.
 pub type Prevote<Block> = grandpa::Prevote<<Block as BlockT>::Hash, NumberFor<Block>>;
+
 /// A precommit message for this chain's block type.
 pub type Precommit<Block> = grandpa::Precommit<<Block as BlockT>::Hash, NumberFor<Block>>;
+
 /// A catch up message for this chain's block type.
 pub type CatchUp<Block> = grandpa::CatchUp<
 	<Block as BlockT>::Hash,
@@ -136,6 +149,7 @@ pub type CatchUp<Block> = grandpa::CatchUp<
 	AuthoritySignature,
 	AuthorityId,
 >;
+
 /// A commit message for this chain's block type.
 pub type Commit<Block> = grandpa::Commit<
 	<Block as BlockT>::Hash,
@@ -143,6 +157,7 @@ pub type Commit<Block> = grandpa::Commit<
 	AuthoritySignature,
 	AuthorityId,
 >;
+
 /// A compact commit message for this chain's block type.
 pub type CompactCommit<Block> = grandpa::CompactCommit<
 	<Block as BlockT>::Hash,
@@ -150,6 +165,7 @@ pub type CompactCommit<Block> = grandpa::CompactCommit<
 	AuthoritySignature,
 	AuthorityId,
 >;
+
 /// A global communication input stream for commits and catch up messages. Not
 /// exposed publicly, used internally to simplify types in the communication
 /// layer.
@@ -663,19 +679,29 @@ pub fn run_grandpa_voter<B, E, Block: BlockT<Hash=H256>, N, RA, SC, X>(
 					// start the new authority set using the block where the
 					// set changed (not where the signal happened!) as the base.
 					let genesis_state = RoundState::genesis((new.canon_hash, new.canon_number));
+					
+					// always start at round 0 when changing sets.
+					let completed_round = CompletedRound {
+							number: 0,
+							state: genesis_state,
+							base: (new.canon_hash, new.canon_number),
+							historical_votes: HistoricalVotes::<Block>::new(),
+					};
+
+					let mut rounds = VecDeque::new();
+					rounds.push_back(completed_round);
+
+					let voters = authority_set.inner().read()
+						.current().1.iter().map(|(a, _)| a.clone()).collect();
+		
+					let completed_rounds = CompletedRounds::new(
+						rounds,
+						new.set_id,
+						voters,
+					);
 
 					let set_state = VoterSetState::Live {
-						// always start at round 0 when changing sets.
-						completed_rounds: CompletedRounds::new(
-							CompletedRound {
-								number: 0,
-								state: genesis_state,
-								base: (new.canon_hash, new.canon_number),
-								votes: Vec::new(),
-							},
-							new.set_id,
-							&*authority_set.inner().read(),
-						),
+						completed_rounds,
 						current_round: HasVoted::No,
 					};
 
diff --git a/core/finality-grandpa/src/observer.rs b/core/finality-grandpa/src/observer.rs
index 2c0818c2d709..ae8ea6349a26 100644
--- a/core/finality-grandpa/src/observer.rs
+++ b/core/finality-grandpa/src/observer.rs
@@ -15,12 +15,14 @@
 // along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
 
 use std::sync::Arc;
+use std::collections::VecDeque;
 
 use futures::prelude::*;
 use futures::future::{self, Loop as FutureLoop};
 
 use grandpa::{
-	BlockNumberOps, Error as GrandpaError, round::State as RoundState, voter, voter_set::VoterSet
+	BlockNumberOps, Error as GrandpaError, round::State as RoundState, voter, voter_set::VoterSet,
+	HistoricalVotes,
 };
 use log::{debug, info, warn};
 
@@ -239,19 +241,26 @@ pub fn run_grandpa_observer<B, E, Block: BlockT<Hash=H256>, N, RA, SC>(
 					// start the new authority set using the block where the
 					// set changed (not where the signal happened!) as the base.
 					let genesis_state = RoundState::genesis((new.canon_hash, new.canon_number));
-
+					let completed_round = CompletedRound {
+						number: 0,
+						state: genesis_state,
+						base: (new.canon_hash, new.canon_number),
+						historical_votes: HistoricalVotes::new(),
+					};
+					let mut rounds = VecDeque::new();
+					rounds.push_back(completed_round);
+					let voters_set = &*authority_set.inner().read();
+					let voters = voters_set
+						.current().1.iter().map(|(a, _)| a.clone()).collect();
+		
+					let completed_rounds = CompletedRounds::new(
+						rounds,
+						new.set_id,
+						voters,
+					);
 					let set_state = VoterSetState::Live::<Block> {
 						// always start at round 0 when changing sets.
-						completed_rounds: CompletedRounds::new(
-							CompletedRound {
-								number: 0,
-								state: genesis_state,
-								base: (new.canon_hash, new.canon_number),
-								votes: Vec::new(),
-							},
-							new.set_id,
-							&*authority_set.inner().read(),
-						),
+						completed_rounds,
 						current_round: HasVoted::No,
 					};