diff --git a/pkgs/applications/version-management/mercurial/4.9.nix b/pkgs/applications/version-management/mercurial/4.9.nix
deleted file mode 100644
index 0a76f7df9704..000000000000
--- a/pkgs/applications/version-management/mercurial/4.9.nix
+++ /dev/null
@@ -1,68 +0,0 @@
-{ lib, stdenv, fetchurl, python2Packages, makeWrapper
-, guiSupport ? false, tk ? null
-, ApplicationServices
-}:
-
-let
-  inherit (python2Packages) docutils hg-git dulwich python;
-
-in python2Packages.buildPythonApplication rec {
-  pname = "mercurial";
-  version = "4.9.1";
-
-  src = fetchurl {
-    url = "https://mercurial-scm.org/release/mercurial-${version}.tar.gz";
-    sha256 = "0iybbkd9add066729zg01kwz5hhc1s6lhp9rrnsmzq6ihyxj3p8v";
-  };
-
-  format = "other";
-
-  inherit python; # pass it so that the same version can be used in hg2git
-
-  nativeBuildInputs = [ makeWrapper ];
-  buildInputs = [ docutils ]
-    ++ lib.optionals stdenv.isDarwin [ ApplicationServices ];
-
-  propagatedBuildInputs = [ hg-git dulwich ];
-
-  makeFlags = [ "PREFIX=$(out)" ];
-
-  postInstall = (lib.optionalString guiSupport
-    ''
-      mkdir -p $out/etc/mercurial
-      cp contrib/hgk $out/bin
-      cat >> $out/etc/mercurial/hgrc << EOF
-      [extensions]
-      hgk=$out/lib/${python.libPrefix}/site-packages/hgext/hgk.py
-      EOF
-      # setting HG so that hgk can be run itself as well (not only hg view)
-      WRAP_TK=" --set TK_LIBRARY ${tk}/lib/${tk.libPrefix}
-                --set HG $out/bin/hg
-                --prefix PATH : ${tk}/bin "
-    '') +
-    ''
-      for i in $(cd $out/bin && ls); do
-        wrapProgram $out/bin/$i \
-          $WRAP_TK
-      done
-
-      # copy hgweb.cgi to allow use in apache
-      mkdir -p $out/share/cgi-bin
-      cp -v hgweb.cgi contrib/hgweb.wsgi $out/share/cgi-bin
-      chmod u+x $out/share/cgi-bin/hgweb.cgi
-
-      # install bash/zsh completions
-      install -v -m644 -D contrib/bash_completion $out/share/bash-completion/completions/_hg
-      install -v -m644 -D contrib/zsh_completion $out/share/zsh/site-functions/_hg
-    '';
-
-  meta = {
-    description = "A fast, lightweight SCM system for very large distributed projects";
-    homepage = "https://www.mercurial-scm.org";
-    downloadPage = "https://www.mercurial-scm.org/release/";
-    license = lib.licenses.gpl2;
-    maintainers = [ lib.maintainers.eraserhd ];
-    updateWalker = true;
-    platforms = lib.platforms.unix;
-  };
-}
diff --git a/pkgs/top-level/aliases.nix b/pkgs/top-level/aliases.nix
index 431e8ef77987..862fa6dbbab8 100644
--- a/pkgs/top-level/aliases.nix
+++ b/pkgs/top-level/aliases.nix
@@ -548,6 +548,7 @@ mapAliases ({
   mopidy-local-sqlite = throw "mopidy-local-sqlite has been removed as it's unmaintained. Its functionality has been merged into the mopidy-local extension."; # added 2020-10-18
   mysql-client = hiPrio mariadb.client;
   memtest86 = memtest86plus; # added 2019-05-08
+  mercurial_4 = throw "mercurial_4 has been removed as it's unmaintained"; # added 2021-10-18
   mesa_noglu = mesa; # added 2019-05-28
   # NOTE: 2018-07-12: legacy alias:
   # grsecurity business is done: https://www.theregister.co.uk/2018/02/08/bruce_perens_grsecurity_anti_slapp/
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 1b1d41f2eebd..faf362da2e76 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -26260,9 +26260,6 @@ with pkgs;
     inherit (xorg) libX11 libXrandr;
   };
 
-  mercurial_4 = callPackage ../applications/version-management/mercurial/4.9.nix {
-    inherit (darwin.apple_sdk.frameworks) ApplicationServices;
-  };
   mercurial = callPackage ../applications/version-management/mercurial {
     inherit (darwin.apple_sdk.frameworks) ApplicationServices;
   };