diff --git a/nixos/modules/services/mail/mailman.nix b/nixos/modules/services/mail/mailman.nix
index 84b0fbc5f6e..f75d6183c3e 100644
--- a/nixos/modules/services/mail/mailman.nix
+++ b/nixos/modules/services/mail/mailman.nix
@@ -454,7 +454,7 @@ in {
   };
 
   meta = {
-    maintainers = with lib.maintainers; [ lheckemann ];
+    maintainers = with lib.maintainers; [ lheckemann qyliss ];
     doc = ./mailman.xml;
   };
 
diff --git a/nixos/modules/services/mail/nullmailer.nix b/nixos/modules/services/mail/nullmailer.nix
index fe3f8ef9b39..09874ca0ed7 100644
--- a/nixos/modules/services/mail/nullmailer.nix
+++ b/nixos/modules/services/mail/nullmailer.nix
@@ -204,6 +204,7 @@ with lib;
       users.${cfg.user} = {
         description = "Nullmailer relay-only mta user";
         group = cfg.group;
+        isSystemUser = true;
       };
 
       groups.${cfg.group} = { };
diff --git a/pkgs/applications/networking/p2p/transmission/default.nix b/pkgs/applications/networking/p2p/transmission/default.nix
index 7e8b6b671cd..363e5f7cfbe 100644
--- a/pkgs/applications/networking/p2p/transmission/default.nix
+++ b/pkgs/applications/networking/p2p/transmission/default.nix
@@ -20,6 +20,7 @@
 , enableSystemd ? stdenv.isLinux
 , enableDaemon ? true
 , enableCli ? true
+, installLib ? false
 }:
 
 let
@@ -47,6 +48,7 @@ in stdenv.mkDerivation {
       "-DENABLE_QT=${mkFlag enableQt}"
       "-DENABLE_DAEMON=${mkFlag enableDaemon}"
       "-DENABLE_CLI=${mkFlag enableCli}"
+      "-DINSTALL_LIB=${mkFlag installLib}"
     ];
 
   nativeBuildInputs = [
diff --git a/pkgs/development/haskell-modules/configuration-common.nix b/pkgs/development/haskell-modules/configuration-common.nix
index b964a5c101a..f313d65508d 100644
--- a/pkgs/development/haskell-modules/configuration-common.nix
+++ b/pkgs/development/haskell-modules/configuration-common.nix
@@ -1244,15 +1244,6 @@ self: super: {
   # Tests disabled and broken override needed because of missing lib chrome-test-utils: https://github.com/reflex-frp/reflex-dom/issues/392
   reflex-dom-core = doDistribute (unmarkBroken (dontCheck (doJailbreak super.reflex-dom-core)));
 
-  # Tests disabled and broken override needed because of missing lib chrome-test-utils: https://github.com/reflex-frp/reflex-dom/issues/392
-  reflex-dom = appendPatch super.reflex-dom (pkgs.fetchpatch {
-    url = https://github.com/reflex-frp/reflex-dom/commit/6aed7b7ebb70372778f1a29a724fcb4de815ba04.patch;
-    sha256 = "1ndqw5r85axynmx55ld6qr8ik1i1mkh6wrnkzpxbwyil2ms8mxn0";
-    stripLen = 2;
-    extraPrefix = "";
-    includes = ["reflex-dom.cabal" ];
-  });
-
   # add unreleased commit fixing version constraint as a patch
   # Can be removed if https://github.com/lpeterse/haskell-utc/issues/8 is resolved
   utc = appendPatch super.utc (pkgs.fetchpatch {
diff --git a/pkgs/development/libraries/libcaca/default.nix b/pkgs/development/libraries/libcaca/default.nix
index ca879a60c7a..f12409f271f 100644
--- a/pkgs/development/libraries/libcaca/default.nix
+++ b/pkgs/development/libraries/libcaca/default.nix
@@ -1,40 +1,75 @@
-{ lib, stdenv, fetchurl, ncurses, zlib, pkg-config, imlib2
-, x11Support ? !stdenv.isDarwin, libX11, libXext
+{ lib
+, stdenv
+, fetchurl
+, imlib2
+, libX11
+, libXext
+, ncurses
+, pkg-config
+, x11Support ? !stdenv.isDarwin
+, zlib
 }:
 
 stdenv.mkDerivation rec {
-  name = "libcaca-0.99.beta19";
+  pname = "libcaca";
+  version = "0.99.beta19";
 
   src = fetchurl {
     urls = [
-      "http://fossies.org/linux/privat/${name}.tar.gz"
-      "http://caca.zoy.org/files/libcaca/${name}.tar.gz"
+      "http://fossies.org/linux/privat/${pname}-${version}.tar.gz"
+      "http://caca.zoy.org/files/libcaca/${pname}-${version}.tar.gz"
     ];
-    sha256 = "1x3j6yfyxl52adgnabycr0n38j9hx2j74la0hz0n8cnh9ry4d2qj";
+    hash = "sha256-EotGfE7QMmTBh0BRcqToMEk0LMjML2VfU6LQ7p03cvQ=";
   };
 
   outputs = [ "bin" "dev" "out" "man" ];
 
   configureFlags = [
     (if x11Support then "--enable-x11" else "--disable-x11")
-    ];
+  ];
 
   NIX_CFLAGS_COMPILE = lib.optionalString (!x11Support) "-DX_DISPLAY_MISSING";
 
   enableParallelBuilding = true;
 
-  propagatedBuildInputs = [ ncurses zlib pkg-config (imlib2.override { inherit x11Support; }) ]
-    ++ lib.optionals x11Support [ libX11 libXext ];
+  nativeBuildInputs = [
+    pkg-config
+  ];
+  buildInputs = [
+    ncurses
+    zlib
+    (imlib2.override { inherit x11Support; })
+  ] ++ lib.optionals x11Support [
+    libX11
+    libXext
+  ];
 
   postInstall = ''
     mkdir -p $dev/bin
     mv $bin/bin/caca-config $dev/bin/caca-config
   '';
 
-  meta = {
-    homepage = "http://libcaca.zoy.org/";
+  meta = with lib; {
+    homepage = "http://caca.zoy.org/wiki/libcaca";
     description = "A graphics library that outputs text instead of pixels";
-    license = lib.licenses.wtfpl;
-    platforms = lib.platforms.unix;
+    longDescription = ''
+      libcaca is a graphics library that outputs text instead of pixels, so that
+      it can work on older video cards or text terminals. It is not unlike the
+      famous ​AAlib library, with the following improvements:
+
+      - Unicode support
+      - 2048 available colours (some devices can only handle 16)
+      - dithering of colour images
+      - advanced text canvas operations (blitting, rotations)
+
+      Libcaca works in a text terminal (and should thus work on all Unix systems
+      including Mac OS X) using the S-Lang or ncurses libraries. It also works
+      natively on DOS and Windows.
+
+      Libcaca was written by Sam Hocevar and Jean-Yves Lamoureux.
+    '';
+    license = licenses.wtfpl;
+    maintainers = with maintainers; [ AndersonTorres ];
+    platforms = platforms.unix;
   };
 }
diff --git a/pkgs/development/ocaml-modules/ezxmlm/default.nix b/pkgs/development/ocaml-modules/ezxmlm/default.nix
index 6d5fe28a8c0..b146b2349cd 100644
--- a/pkgs/development/ocaml-modules/ezxmlm/default.nix
+++ b/pkgs/development/ocaml-modules/ezxmlm/default.nix
@@ -1,14 +1,14 @@
-{ lib, fetchFromGitHub, buildDunePackage, xmlm }:
+{ lib, fetchurl, buildDunePackage, xmlm }:
 
 buildDunePackage rec {
   pname = "ezxmlm";
-  version = "1.0.2";
+  version = "1.1.0";
 
-  src = fetchFromGitHub {
-    owner = "avsm";
-    repo = pname;
-    rev = "v${version}";
-    sha256 = "1dgr61f0hymywikn67inq908x5adrzl3fjx3v14l9k46x7kkacl9";
+  useDune2 = true;
+
+  src = fetchurl {
+    url = "https://github.com/mirage/ezxmlm/releases/download/v${version}/ezxmlm-v${version}.tbz";
+    sha256 = "123dn4h993mlng9gzf4nc6mw75ja7ndcxkbkwfs48j5jk1z05j6d";
   };
 
   propagatedBuildInputs = [ xmlm ];
@@ -27,7 +27,7 @@ buildDunePackage rec {
       just fine with it if you decide to switch over.
     '';
     maintainers = [ maintainers.carlosdagos ];
-    inherit (src.meta) homepage;
+    homepage = "https://github.com/mirage/ezxmlm/";
     license = licenses.isc;
   };
 }
diff --git a/pkgs/development/python-modules/django-mailman3/default.nix b/pkgs/development/python-modules/django-mailman3/default.nix
index 54cde59a4bd..7e99d22693f 100644
--- a/pkgs/development/python-modules/django-mailman3/default.nix
+++ b/pkgs/development/python-modules/django-mailman3/default.nix
@@ -27,6 +27,6 @@ buildPythonPackage rec {
     description = "Django library for Mailman UIs";
     homepage = "https://gitlab.com/mailman/django-mailman3";
     license = licenses.gpl3Plus;
-    maintainers = with maintainers; [ globin peti ];
+    maintainers = with maintainers; [ globin peti qyliss ];
   };
 }
diff --git a/pkgs/development/python-modules/mailman-hyperkitty/default.nix b/pkgs/development/python-modules/mailman-hyperkitty/default.nix
index 1d3b69f6bf2..d5bf6457336 100644
--- a/pkgs/development/python-modules/mailman-hyperkitty/default.nix
+++ b/pkgs/development/python-modules/mailman-hyperkitty/default.nix
@@ -21,6 +21,6 @@ buildPythonPackage rec {
     description = "Mailman archiver plugin for HyperKitty";
     homepage = "https://gitlab.com/mailman/mailman-hyperkitty";
     license = licenses.gpl3;
-    maintainers = with maintainers; [ globin peti ];
+    maintainers = with maintainers; [ globin peti qyliss ];
   };
 }
diff --git a/pkgs/development/python-modules/mailmanclient/default.nix b/pkgs/development/python-modules/mailmanclient/default.nix
index 0c981a6789d..c19daed1b9f 100644
--- a/pkgs/development/python-modules/mailmanclient/default.nix
+++ b/pkgs/development/python-modules/mailmanclient/default.nix
@@ -17,6 +17,6 @@ buildPythonPackage rec {
     description = "REST client for driving Mailman 3";
     license = licenses.lgpl3;
     platforms = platforms.linux;
-    maintainers = with maintainers; [ peti globin ];
+    maintainers = with maintainers; [ peti globin qyliss ];
   };
 }
diff --git a/pkgs/development/python-modules/py/default.nix b/pkgs/development/python-modules/py/default.nix
index 8c38723207a..26afa14c1ef 100644
--- a/pkgs/development/python-modules/py/default.nix
+++ b/pkgs/development/python-modules/py/default.nix
@@ -20,7 +20,7 @@ buildPythonPackage rec {
 
   meta = with lib; {
     description = "Library with cross-python path, ini-parsing, io, code, log facilities";
-    homepage = "https://pylib.readthedocs.org/";
+    homepage = "https://py.readthedocs.io/";
     license = licenses.mit;
   };
 }
diff --git a/pkgs/misc/vscode-extensions/default.nix b/pkgs/misc/vscode-extensions/default.nix
index 197aacb48a0..c49c2b89dbd 100644
--- a/pkgs/misc/vscode-extensions/default.nix
+++ b/pkgs/misc/vscode-extensions/default.nix
@@ -427,8 +427,8 @@ let
           mktplcRef = {
             name = "github-vscode-theme";
             publisher = "github";
-            version = "3.0.0";
-            sha256 = "1a77mbx75xfsfdlhgzghj9i7ik080bppc3jm8c00xp6781987fpa";
+            version = "4.0.2";
+            sha256 = "06mysdwjh7km874rrk0xc0xxaqx15b4a7x1i8dly440h8w3ng5bs";
           };
           meta = with lib; {
             description = "GitHub theme for VS Code";
diff --git a/pkgs/servers/mail/mailman/default.nix b/pkgs/servers/mail/mailman/default.nix
index 7f1e02fd76e..392239a7140 100644
--- a/pkgs/servers/mail/mailman/default.nix
+++ b/pkgs/servers/mail/mailman/default.nix
@@ -54,6 +54,6 @@ buildPythonPackage rec {
     homepage = "https://www.gnu.org/software/mailman/";
     description = "Free software for managing electronic mail discussion and newsletter lists";
     license = lib.licenses.gpl3Plus;
-    maintainers = with lib.maintainers; [ peti ];
+    maintainers = with lib.maintainers; [ peti qyliss ];
   };
 }
diff --git a/pkgs/servers/mail/mailman/hyperkitty.nix b/pkgs/servers/mail/mailman/hyperkitty.nix
index 054d9dcf91a..5500f465852 100644
--- a/pkgs/servers/mail/mailman/hyperkitty.nix
+++ b/pkgs/servers/mail/mailman/hyperkitty.nix
@@ -42,6 +42,6 @@ buildPythonPackage rec {
     description = "Archiver for GNU Mailman v3";
     license = lib.licenses.gpl3;
     platforms = lib.platforms.linux;
-    maintainers = with lib.maintainers; [ peti globin ];
+    maintainers = with lib.maintainers; [ peti globin qyliss ];
   };
 }
diff --git a/pkgs/servers/mail/mailman/postorius.nix b/pkgs/servers/mail/mailman/postorius.nix
index 189e152fce0..222a21bcb7f 100644
--- a/pkgs/servers/mail/mailman/postorius.nix
+++ b/pkgs/servers/mail/mailman/postorius.nix
@@ -23,6 +23,6 @@ buildPythonPackage rec {
     homepage = "https://docs.mailman3.org/projects/postorius";
     description = "Web-based user interface for managing GNU Mailman";
     license = licenses.gpl3Plus;
-    maintainers = with maintainers; [ globin peti ];
+    maintainers = with maintainers; [ globin peti qyliss ];
   };
 }
diff --git a/pkgs/tools/misc/bat-extras/default.nix b/pkgs/tools/misc/bat-extras/default.nix
index 323099f02c6..4fb09f4d8dc 100644
--- a/pkgs/tools/misc/bat-extras/default.nix
+++ b/pkgs/tools/misc/bat-extras/default.nix
@@ -21,15 +21,13 @@ let
   # This includes the complete source so the per-script derivations can run the tests.
   core = stdenv.mkDerivation rec {
     pname   = "bat-extras";
-    # there hasn't been a release since 2020-05-01 but there are important bugfixes
-    # to the test suite so we'll pull the latest commit as of 2020-06-17.
-    version = "20200515-dev"; # latest commit was dated 2020-05-15
+    version = "2021.04.06";
 
     src = fetchFromGitHub {
       owner  = "eth-p";
       repo   = pname;
-      rev    = "3029b6749f61f7514e9eef30e035cfab0e31eb1d";
-      sha256 = "08mb94k2n182ql97c5s5j1v7np25ivynn5g0418whrx11ra41wr7";
+      rev    = "v${version}";
+      sha256 = "sha256-MphI2n+oHZrw8bPohNGeGdST5LS1c6s/rKqtpcR9cLo=";
       fetchSubmodules = true;
     };
 
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 77dad75554f..cd22f4c9dac 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -26203,6 +26203,11 @@ in
   transcode = callPackage ../applications/audio/transcode { };
 
   transmission = callPackage ../applications/networking/p2p/transmission { };
+  libtransmission = transmission.override {
+    installLib = true;
+    enableDaemon = false;
+    enableCli = false;
+  };
   transmission-gtk = transmission.override { enableGTK3 = true; };
   transmission-qt = transmission.override { enableQt = true; };