diff --git a/pkgs/applications/networking/libcoap/default.nix b/pkgs/applications/networking/libcoap/default.nix
index 239ef8516a7f..f8c4c44715e5 100644
--- a/pkgs/applications/networking/libcoap/default.nix
+++ b/pkgs/applications/networking/libcoap/default.nix
@@ -15,13 +15,13 @@
 }:
 stdenv.mkDerivation rec {
   pname = "libcoap";
-  version = "4.3.5";
+  version = "4.3.5a";
   src = fetchFromGitHub {
     repo = "libcoap";
     owner = "obgm";
     rev = "v${version}";
     fetchSubmodules = true;
-    hash = "sha256-QNrsR6VarZ2favvTZ9pMhVafwF2fOjYLKcyNqZyUl6s=";
+    hash = "sha256-mLVGIG2JkWMlnZOlLxFTZVGM0nF6q2PKJoEo0s4Vq54=";
   };
   nativeBuildInputs = [
     automake