diff --git a/pkgs/servers/mastodon/source.nix b/pkgs/servers/mastodon/source.nix
index 5ab107958827..995b58476d78 100644
--- a/pkgs/servers/mastodon/source.nix
+++ b/pkgs/servers/mastodon/source.nix
@@ -1,11 +1,14 @@
 # This file was generated by pkgs.mastodon.updateScript.
 { fetchFromGitHub, applyPatches }:
-applyPatches {
+let
   version = "4.1.9";
+in
+applyPatches {
+  inherit version;
   src = fetchFromGitHub {
     owner = "mastodon";
     repo = "mastodon";
-    rev = "v4.1.9";
+    rev = "${version}";
     hash = "sha256-xpE/mg2AeioW6NThUjLS+SBxGavG4w1xtp3BOMADfYo=";
   };
   patches = [];
diff --git a/pkgs/servers/mastodon/update.sh b/pkgs/servers/mastodon/update.sh
index b30aee1ec06c..6955f9e61805 100755
--- a/pkgs/servers/mastodon/update.sh
+++ b/pkgs/servers/mastodon/update.sh
@@ -82,12 +82,15 @@ HASH=$(echo "$JSON" | jq -r .hash)
 cat > source.nix << EOF
 # This file was generated by pkgs.mastodon.updateScript.
 { fetchFromGitHub, applyPatches }:
-applyPatches {
+let
   version = "$VERSION";
+in
+applyPatches {
+  inherit version;
   src = fetchFromGitHub {
     owner = "$OWNER";
     repo = "$REPO";
-    rev = "$REVISION";
+    rev = "\${version}";
     hash = "$HASH";
   };
   patches = [$PATCHES];