diff --git a/pkgs/development/libraries/libunibreak/default.nix b/pkgs/development/libraries/libunibreak/default.nix
index 8c6650df3cb6..d30c84b52a2e 100644
--- a/pkgs/development/libraries/libunibreak/default.nix
+++ b/pkgs/development/libraries/libunibreak/default.nix
@@ -5,7 +5,7 @@ stdenv.mkDerivation rec {
   version = "4.3";
 
   src = let
-      rev_version = stdenv.lib.replaceStrings ["-"] ["_"] version;
+      rev_version = stdenv.lib.replaceStrings ["."] ["_"] version;
   in fetchFromGitHub {
     owner = "adah1972";
     repo = pname;