diff --git a/dune-project b/dune-project
index 3381d7ef..d25d423c 100644
--- a/dune-project
+++ b/dune-project
@@ -5,6 +5,7 @@
 (source (github ocurrent/obuilder))
 (authors "talex5@gmail.com")
 (maintainers "talex5@gmail.com")
+(license "Apache-2.0")
 (documentation "https://ocurrent.github.io/obuilder/")
 (package
  (name obuilder)
@@ -18,7 +19,7 @@
   logs
   (cmdliner (>= 1.1.0))
   (tar-unix (>= 2.0.0))
-  yojson
+  (yojson (>= "1.6.0"))
   sexplib
   ppx_deriving
   ppx_sexp_conv
@@ -26,7 +27,9 @@
   sqlite3
   (obuilder-spec (= :version))
   (ocaml (>= 4.10.0))
-  (alcotest-lwt :with-test)))
+  (alcotest-lwt :with-test))
+ (conflicts
+  (result (< "1.5"))))
 (package
  (name obuilder-spec)
  (synopsis "Build specification format")
diff --git a/obuilder-spec.opam b/obuilder-spec.opam
index aac0d75b..e900c02a 100644
--- a/obuilder-spec.opam
+++ b/obuilder-spec.opam
@@ -5,6 +5,7 @@ description:
   "A library for constructing, reading and writing OBuilder build specification files."
 maintainer: ["talex5@gmail.com"]
 authors: ["talex5@gmail.com"]
+license: "Apache-2.0"
 homepage: "https://github.com/ocurrent/obuilder"
 doc: "https://ocurrent.github.io/obuilder/"
 bug-reports: "https://github.com/ocurrent/obuilder/issues"
diff --git a/obuilder.opam b/obuilder.opam
index b736cb51..9732d0b5 100644
--- a/obuilder.opam
+++ b/obuilder.opam
@@ -5,6 +5,7 @@ description:
   "OBuilder takes a build script (similar to a Dockerfile) and performs the steps in it in a sandboxed environment."
 maintainer: ["talex5@gmail.com"]
 authors: ["talex5@gmail.com"]
+license: "Apache-2.0"
 homepage: "https://github.com/ocurrent/obuilder"
 doc: "https://ocurrent.github.io/obuilder/"
 bug-reports: "https://github.com/ocurrent/obuilder/issues"
@@ -16,7 +17,7 @@ depends: [
   "logs"
   "cmdliner" {>= "1.1.0"}
   "tar-unix" {>= "2.0.0"}
-  "yojson"
+  "yojson" {>= "1.6.0"}
   "sexplib"
   "ppx_deriving"
   "ppx_sexp_conv"
@@ -27,6 +28,9 @@ depends: [
   "alcotest-lwt" {with-test}
   "odoc" {with-doc}
 ]
+conflicts: [
+  "result" {< "1.5"}
+]
 build: [
   ["dune" "subst"] {dev}
   [