diff --git a/pkgs/development/python-modules/pycrdt-websocket/default.nix b/pkgs/development/python-modules/pycrdt-websocket/default.nix
index 573c4917bbc5..7a3a2362de00 100644
--- a/pkgs/development/python-modules/pycrdt-websocket/default.nix
+++ b/pkgs/development/python-modules/pycrdt-websocket/default.nix
@@ -26,14 +26,14 @@
 
 buildPythonPackage rec {
   pname = "pycrdt-websocket";
-  version = "0.16.0";
+  version = "0.15.5";
   pyproject = true;
 
   src = fetchFromGitHub {
     owner = "jupyter-server";
     repo = "pycrdt-websocket";
-    tag = version;
-    hash = "sha256-Qux8IxJR1nGbdpGz7RZBKJjYN0qfwfEpd2UDlduOna0=";
+    tag = "v${version}";
+    hash = "sha256-piNd85X5YsTAOC9frYQRDyb/DPfzZicIPJ+bEVzgOsU=";
   };
 
   build-system = [ hatchling ];
@@ -77,7 +77,7 @@ buildPythonPackage rec {
   meta = {
     description = "WebSocket Connector for pycrdt";
     homepage = "https://github.com/jupyter-server/pycrdt-websocket";
-    changelog = "https://github.com/jupyter-server/pycrdt-websocket/blob/${src.tag}/CHANGELOG.md";
+    changelog = "https://github.com/jupyter-server/pycrdt-websocket/blob/v${version}/CHANGELOG.md";
     license = lib.licenses.mit;
     teams = [ lib.teams.jupyter ];
   };