diff --git a/pkgs/os-specific/linux/linuxptp/default.nix b/pkgs/os-specific/linux/linuxptp/default.nix
index c9de5f874a3..4f58c9f3f2a 100644
--- a/pkgs/os-specific/linux/linuxptp/default.nix
+++ b/pkgs/os-specific/linux/linuxptp/default.nix
@@ -27,7 +27,7 @@ stdenv.mkDerivation rec {
     description = "Implementation of the Precision Time Protocol (PTP) according to IEEE standard 1588 for Linux";
     homepage = "http://linuxptp.sourceforge.net/";
     maintainers = [ maintainers.markuskowa ];
-    license = licenses.gpl2;
+    license = licenses.gpl2Only;
     platforms = platforms.linux;
   };
 }