libktorrent: 2.0.1 -> 2.1

pkgs/development/libraries/libktorrent/default.nix

···
 , boost, gmp, qca-qt5, libgcrypt
 }:
 
-stdenv.mkDerivation rec {
-  name = "libktorrent-2.0.1";
+let
+    mainVersion = "5.1";
+
+in stdenv.mkDerivation rec {
+  name = "libktorrent-2.1";
 
   src = fetchurl {
-    url = http://download.kde.org/stable/ktorrent/5.0/libktorrent-2.0.1.tar.xz;
-    sha256 = "0hiz4wm8jkymp24r6f1g8svj3pw9qspbjajf512m3j8s3bhrw3f7";
+    url    = "mirror://kde/stable/ktorrent/${mainVersion}/${name}.tar.xz";
+    sha256 = "0vz2dwc4xd80q56g6r5bx5wqdl9fxcibxmw2irahqhbkxk7drvry";
   };
 
   outputs = [ "out" "dev" ];
 
   nativeBuildInputs = [ cmake extra-cmake-modules ];
+
   buildInputs = [ karchive kcrash ki18n kio solid qca-qt5 libgcrypt ];
 
   propagatedBuildInputs = [ gmp boost ];
 
   enableParallelBuilding = true;
 
-  meta = {
+  passthru = {
+    inherit mainVersion;
+  };
+
+  meta = with stdenv.lib; {
     description = "A BitTorrent library used by KTorrent";
-    homepage = https://www.kde.org/applications/internet/ktorrent/;
-    maintainers = [ stdenv.lib.maintainers.eelco ];
-    platforms = stdenv.lib.platforms.linux;
+    homepage    = https://www.kde.org/applications/internet/ktorrent/;
+    maintainers = with maintainers; [ eelco ];
+    platforms   = platforms.linux;
   };
 }