diff --git a/pkgs/development/python-modules/cmdstanpy/default.nix b/pkgs/development/python-modules/cmdstanpy/default.nix
index f0de12dcc8b304d..cb31be20a1702cc 100644
--- a/pkgs/development/python-modules/cmdstanpy/default.nix
+++ b/pkgs/development/python-modules/cmdstanpy/default.nix
@@ -2,7 +2,6 @@
   lib,
   buildPythonPackage,
   fetchFromGitHub,
-  fetchpatch,
   substituteAll,
   cmdstan,
   setuptools,
@@ -32,11 +31,6 @@ buildPythonPackage rec {
       src = ./use-nix-cmdstan-path.patch;
       cmdstan = "${cmdstan}/opt/cmdstan";
     })
-    # Fix seed-dependent tests
-    (fetchpatch {
-      url = "https://github.com/stan-dev/cmdstanpy/commit/c72acd0b8123c02b47d5d583bdd7d8408b04562c.patch";
-      hash = "sha256-cliyDDko4spYa62DMwWBavy5pePkofJo4Kf8I0RzueM=";
-    })
   ];
 
   postPatch = ''
diff --git a/pkgs/development/python-modules/stanio/default.nix b/pkgs/development/python-modules/stanio/default.nix
index 27d754a7d8944eb..a87e753c1886f43 100644
--- a/pkgs/development/python-modules/stanio/default.nix
+++ b/pkgs/development/python-modules/stanio/default.nix
@@ -9,14 +9,14 @@
 
 buildPythonPackage rec {
   pname = "stanio";
-  version = "0.5.0";
+  version = "0.5.1";
   pyproject = true;
 
   disabled = pythonOlder "3.8";
 
   src = fetchPypi {
     inherit pname version;
-    hash = "sha256-3uQpMU2WXzkBga+o/3/4FERG7rWMwlR8zBCLpz5nROI=";
+    hash = "sha256-NI1S+UfexDHhGPS2AcTFKWkpuGQB1NTdWqk3Ow1K5Kw=";
   };
 
   nativeBuildInputs = [ setuptools ];