diff --git a/nixos/modules/services/hardware/bluetooth.nix b/nixos/modules/services/hardware/bluetooth.nix
index ef2fce613f2..de0d4803211 100644
--- a/nixos/modules/services/hardware/bluetooth.nix
+++ b/nixos/modules/services/hardware/bluetooth.nix
@@ -2,9 +2,7 @@
 
 with lib;
 let
-  isBluez4 = config.services.xserver.desktopManager.kde4.enable;
-  bluez-bluetooth = if isBluez4 then pkgs.bluez4 else pkgs.bluez;
-
+  bluez-bluetooth = pkgs.bluez;
 in
 
 {
@@ -38,7 +36,7 @@ in
       aliases = [ "dbus-org.bluez.service" ];
     };
 
-    systemd.user.services.obex = mkIf (!isBluez4) {
+    systemd.user.services.obex = {
       aliases = [ "dbus-org.bluez.obex.service" ];
     };
 
diff --git a/nixos/modules/services/networking/quassel.nix b/nixos/modules/services/networking/quassel.nix
index edcc12170b2..9b06cccca79 100644
--- a/nixos/modules/services/networking/quassel.nix
+++ b/nixos/modules/services/networking/quassel.nix
@@ -25,12 +25,12 @@ in
 
       package = mkOption {
         type = types.package;
-        default = pkgs.kde4.quasselDaemon;
-        defaultText = "pkgs.kde4.quasselDaemon";
+        default = pkgs.quasselDaemon_qt5;
+        defaultText = "pkgs.quasselDaemon_qt5";
         description = ''
           The package of the quassel daemon.
         '';
-        example = literalExample "pkgs.quasselDaemon";
+        example = literalExample "pkgs.quasselDaemon_qt5";
       };
 
       interfaces = mkOption {
diff --git a/nixos/modules/services/x11/desktop-managers/default.nix b/nixos/modules/services/x11/desktop-managers/default.nix
index 144e4aada27..1f7a925ed05 100644
--- a/nixos/modules/services/x11/desktop-managers/default.nix
+++ b/nixos/modules/services/x11/desktop-managers/default.nix
@@ -18,9 +18,8 @@ in
   # determines the default: later modules (if enabled) are preferred.
   # E.g., if KDE is enabled, it supersedes xterm.
   imports = [
-    ./none.nix ./xterm.nix ./xfce.nix ./kde4.nix ./kde5.nix
-    ./lumina.nix ./lxqt.nix ./enlightenment.nix ./gnome3.nix
-    ./kodi.nix
+    ./none.nix ./xterm.nix ./xfce.nix ./kde5.nix ./lumina.nix
+    ./lxqt.nix ./enlightenment.nix ./gnome3.nix ./kodi.nix
   ];
 
   options = {
diff --git a/nixos/modules/services/x11/desktop-managers/kde5.nix b/nixos/modules/services/x11/desktop-managers/kde5.nix
index 8f081a1e9d2..644fd8d7752 100644
--- a/nixos/modules/services/x11/desktop-managers/kde5.nix
+++ b/nixos/modules/services/x11/desktop-managers/kde5.nix
@@ -50,10 +50,6 @@ in
     })
 
     (mkIf (xcfg.enable && cfg.enable) {
-
-      warnings = optional config.services.xserver.desktopManager.kde4.enable
-        "KDE 4 should not be enabled at the same time as KDE 5";
-
       services.xserver.desktopManager.session = singleton {
         name = "kde5";
         bgSupport = true;
diff --git a/nixos/release-combined.nix b/nixos/release-combined.nix
index 70b29aa23a5..6c048e8a0ac 100644
--- a/nixos/release-combined.nix
+++ b/nixos/release-combined.nix
@@ -72,7 +72,6 @@ in rec {
         (all nixos.tests.ecryptfs)
         (all nixos.tests.ipv6)
         (all nixos.tests.i3wm)
-        (all nixos.tests.kde4)
         (all nixos.tests.kde5)
         #(all nixos.tests.lightdm)
         (all nixos.tests.login)
diff --git a/nixos/release.nix b/nixos/release.nix
index 0f298188c6c..c061b9801a0 100644
--- a/nixos/release.nix
+++ b/nixos/release.nix
@@ -255,7 +255,6 @@ in rec {
   tests.influxdb = callTest tests/influxdb.nix {};
   tests.ipv6 = callTest tests/ipv6.nix {};
   tests.jenkins = callTest tests/jenkins.nix {};
-  tests.kde4 = callTest tests/kde4.nix {};
   tests.kde5 = callTest tests/kde5.nix {};
   tests.keymap = callSubTests tests/keymap.nix {};
   tests.initrdNetwork = callTest tests/initrd-network.nix {};