Running nixpkgs-update (https://nix-community.org/update-bot/) with UPDATE_INFO: ams unstable-2019-04-27 -> 2.2.1 https://repology.org/project/alsamodularsynth/versions
attrpath: ams
Checking auto update branch...
No auto update branch exists
[version] 
[version] updated version and sha256
[rustCrateVersion] 
[rustCrateVersion] No cargoHash found
[golangModuleVersion] 
[golangModuleVersion] Not a buildGoModule package with vendorHash
[npmDepsVersion] 
[npmDepsVersion] No npmDepsHash
[updateScript] 
[updateScript] skipping because derivation has no updateScript
Diff after rewrites:
diff --git a/pkgs/by-name/am/ams/package.nix b/pkgs/by-name/am/ams/package.nix
index 39f6ab2cebe3..5917cd32214b 100644
--- a/pkgs/by-name/am/ams/package.nix
+++ b/pkgs/by-name/am/ams/package.nix
@@ -14,11 +14,11 @@
 
 stdenv.mkDerivation {
   pname = "ams";
-  version = "unstable-2019-04-27";
+  version = "2.2.1";
 
   src = fetchgit {
     url = "https://git.code.sf.net/p/alsamodular/ams.git";
-    sha256 = "0qdyz5llpa94f3qx1xi1mz97vl5jyrj1mqff28p5g9i5rxbbk8z9";
+    sha256 = "sha256-6aO5Vs8lplcuEs7hGmT2stB90q8h9tDxcCSpS2n5vmE=";
     rev = "3250bbcfea331c4fcb9845305eebded80054973d";
   };
 

rev equal; no update necessary