diff --git a/pkgs/development/python-modules/mocket/default.nix b/pkgs/development/python-modules/mocket/default.nix
index 73a3b07a64c3..ff400c6ed20b 100644
--- a/pkgs/development/python-modules/mocket/default.nix
+++ b/pkgs/development/python-modules/mocket/default.nix
@@ -27,6 +27,11 @@ buildPythonPackage rec {
     sha256 = "1vvlbnbypd4z1pjlvhwhd89fn0mis5acfx4v25f1mfl04k63ffah";
   };
 
+  postPatch = ''
+    substituteInPlace requirements.txt \
+      --replace "decorator>=4.0.0,<5" "decorator>=4.0.0,<6"
+  '';
+
   propagatedBuildInputs = [
     decorator
     http-parser
@@ -54,6 +59,8 @@ buildPythonPackage rec {
   ];
 
   disabledTests = [
+    # incompatible with decorator>=5
+    "test_patch"
     # tests that require network access (like DNS lookups)
     "test_truesendall"
     "test_truesendall_with_chunk_recording"