diff --git a/pkgs/python-packages/pyln-proto/default.nix b/pkgs/python-packages/pyln-proto/default.nix
index 9a7352b..b35b2e9 100644
--- a/pkgs/python-packages/pyln-proto/default.nix
+++ b/pkgs/python-packages/pyln-proto/default.nix
@@ -16,6 +16,11 @@ buildPythonPackage rec {
 
   inherit (clightning) src;
 
+  postPatch = ''
+    substituteInPlace pyproject.toml \
+      --replace-fail 'coincurve==20.0.0' 'coincurve==21.0.0'
+  '';
+
   nativeBuildInputs = [ hatchling ];
 
   propagatedBuildInputs = [