diff --git a/pkgs/development/libraries/tcllib/default.nix b/pkgs/development/libraries/tcllib/default.nix
index 40e137204e26..b1add708902f 100644
--- a/pkgs/development/libraries/tcllib/default.nix
+++ b/pkgs/development/libraries/tcllib/default.nix
@@ -2,11 +2,11 @@
 
 stdenv.mkDerivation rec {
   pname = "tcllib";
-  version = "1.19";
+  version = "1.20";
 
   src = fetchurl {
     url = "mirror://sourceforge/tcllib/tcllib-${version}.tar.gz";
-    sha256 = "173abxaazdmf210v651708ab6h7xhskvd52krxk6ifam337qgzh1";
+    sha256 = "0wax281h6ksz974a5qpfgf9y34lmlpd8i87lkm1w94ybbd3rgc73";
   };
 
   passthru = {