diff --git a/ops/nixos/laputa/default.nix b/ops/nixos/laputa/default.nix
index b7141fe28a..4c8d8e4628 100644
--- a/ops/nixos/laputa/default.nix
+++ b/ops/nixos/laputa/default.nix
@@ -122,7 +122,7 @@
         Users.HideUsers = "deployer";
       };
     };
-    defaultSession = "plasmawayland";
+    defaultSession = "plasma";
   };
 
   boot.initrd.systemd.enable = true;
diff --git a/ops/nixos/lib/home-manager/graphical-client.nix b/ops/nixos/lib/home-manager/graphical-client.nix
index da6c630dfb..ecfacb1f6b 100644
--- a/ops/nixos/lib/home-manager/graphical-client.nix
+++ b/ops/nixos/lib/home-manager/graphical-client.nix
@@ -11,7 +11,7 @@
     };
     qt = {
       enable = true;
-      platformTheme = "gtk";
+      platformTheme.name = "gtk";
     };
 
     home.packages = lib.mkAfter (with pkgs; [
diff --git a/ops/nixos/lib/plasma.nix b/ops/nixos/lib/plasma.nix
index 26b7a544c9..20751d3666 100644
--- a/ops/nixos/lib/plasma.nix
+++ b/ops/nixos/lib/plasma.nix
@@ -7,16 +7,10 @@
   config = {
     my.home-manager.imports = lib.mkAfter [ ./home-manager/plasma.nix ];
 
-    services.xserver.desktopManager.plasma5 = {
+    services.desktopManager.plasma6 = {
       enable = true;
-      useQtScaling = true;
     };
 
     qt.platformTheme = "kde";
-
-    environment.systemPackages = with pkgs.libsForQt5; [
-      # Bismuth, tiling window manager
-      bismuth
-    ];
   };
 }
diff --git a/ops/nixos/nausicaa/default.nix b/ops/nixos/nausicaa/default.nix
index 5a838d1b74..7ffe8532ce 100644
--- a/ops/nixos/nausicaa/default.nix
+++ b/ops/nixos/nausicaa/default.nix
@@ -175,7 +175,7 @@ in {
         Users.HideUsers = "deployer";
       };
     };
-    defaultSession = "plasmawayland";
+    defaultSession = "plasma";
   };
 
   hardware.opengl.driSupport32Bit = true;
diff --git a/ops/nixos/porcorosso/default.nix b/ops/nixos/porcorosso/default.nix
index f6c1bf0a1a..ac3b9d440f 100644
--- a/ops/nixos/porcorosso/default.nix
+++ b/ops/nixos/porcorosso/default.nix
@@ -193,7 +193,7 @@ in {
         Users.HideUsers = "deployer";
       };
     };
-    defaultSession = "plasmawayland";
+    defaultSession = "plasma";
   };
 
   boot.initrd.systemd.enable = true;