diff --git a/flake.lock b/flake.lock
index a0f11aa..d782eb2 100644
--- a/flake.lock
+++ b/flake.lock
@@ -27,11 +27,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1649711426,
-        "narHash": "sha256-tn5Hu9QkG6LhdgEOe+6cmULPeRCW0UY4o/GHU0viLu0=",
+        "lastModified": 1649887911,
+        "narHash": "sha256-Af0Ppb1RZ7HWuxUvF0/O7h3cy8tqU2eKFyVwyA1ZD+w=",
         "owner": "nix-community",
         "repo": "home-manager",
-        "rev": "7049cf37a90e19ead7a379ce1c76dccea29450c4",
+        "rev": "7244c6715cb8f741f3b3e1220a9279e97b2ed8f5",
         "type": "github"
       },
       "original": {
@@ -43,11 +43,11 @@
     },
     "nixos-hardware": {
       "locked": {
-        "lastModified": 1649660850,
-        "narHash": "sha256-x8ZE4B+EuA9dCEJKNzT59yQjzotVMnGYU5GMoqMLk3A=",
+        "lastModified": 1649849514,
+        "narHash": "sha256-zQyTr2UebTKUh1KLyLtevhHsM8umPK1LfQLGUGjRjiQ=",
         "owner": "NixOS",
         "repo": "nixos-hardware",
-        "rev": "f4160a629bac3538939a3005c8b5c7fb320bcf59",
+        "rev": "1a0ccdbf4583ed0fce37eea7955e8ef90f840a9f",
         "type": "github"
       },
       "original": {
@@ -57,38 +57,6 @@
       }
     },
     "nixpkgs-nixos-2111": {
-      "locked": {
-        "lastModified": 1647490331,
-        "narHash": "sha256-Jcc+vHNDN3KDWuzGNTl3A24ICGovPneJDejiN2t57QI=",
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "2c66a7a6e036971c4847cca424125f55b9eb0b0b",
-        "type": "github"
-      },
-      "original": {
-        "owner": "NixOS",
-        "ref": "nixos-21.11",
-        "repo": "nixpkgs",
-        "type": "github"
-      }
-    },
-    "nixpkgs-nixos-unstable": {
-      "locked": {
-        "lastModified": 1647297614,
-        "narHash": "sha256-ulGq3W5XsrBMU/u5k9d4oPy65pQTkunR4HKKtTq0RwY=",
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "73ad5f9e147c0d2a2061f1d4bd91e05078dc0b58",
-        "type": "github"
-      },
-      "original": {
-        "owner": "NixOS",
-        "ref": "nixos-unstable",
-        "repo": "nixpkgs",
-        "type": "github"
-      }
-    },
-    "nixpkgs-stable": {
       "locked": {
         "lastModified": 1649619156,
         "narHash": "sha256-p0q4zpuKMwrzGF+5ZU7Thnpac5TinhDI9jr2mBxhV4w=",
@@ -104,7 +72,7 @@
         "type": "github"
       }
     },
-    "nixpkgs-unstable": {
+    "nixpkgs-nixos-unstable": {
       "locked": {
         "lastModified": 1649497218,
         "narHash": "sha256-groqC9m1P4hpnL6jQvZ3C8NEtduhdkvwGT0+0LUrcYw=",
@@ -120,17 +88,49 @@
         "type": "github"
       }
     },
+    "nixpkgs-stable": {
+      "locked": {
+        "lastModified": 1650244918,
+        "narHash": "sha256-DsS5nxjTpnoUC4pNXJI1rit7TnDTij8vQDa5PtcDCD0=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "7b38b03d76ab71bdc8dc325e3f6338d984cc35ca",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-21.11",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs-unstable": {
+      "locked": {
+        "lastModified": 1650161686,
+        "narHash": "sha256-70ZWAlOQ9nAZ08OU6WY7n4Ij2kOO199dLfNlvO/+pf8=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "1ffba9f2f683063c2b14c9f4d12c55ad5f4ed887",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
     "qois-infrastructure": {
       "inputs": {
         "nixpkgs-nixos-2111": "nixpkgs-nixos-2111",
         "nixpkgs-nixos-unstable": "nixpkgs-nixos-unstable"
       },
       "locked": {
-        "lastModified": 1649702020,
-        "narHash": "sha256-wUFuh5CKX7fzTvcHZKF7EOaN5eWG/yOql/e+aG8LM7I=",
-        "ref": "master",
-        "rev": "f7e0a51e165a6f2cd35e9edd001db504ea6fe5f7",
-        "revCount": 216,
+        "lastModified": 1649748318,
+        "narHash": "sha256-aLMS2Fb67jMjvz0uiysZuYhzdBz9/9t+Mf8PjIKDEa8=",
+        "ref": "38-migrate-to-nix-flakes",
+        "rev": "ccee28f669dda9491d934a0ac00ac9b48fc5e326",
+        "revCount": 217,
         "type": "git",
         "url": "file:///etc/nixos/qois-infrastructure"
       },
@@ -146,7 +146,28 @@
         "nixos-hardware": "nixos-hardware",
         "nixpkgs-stable": "nixpkgs-stable",
         "nixpkgs-unstable": "nixpkgs-unstable",
-        "qois-infrastructure": "qois-infrastructure"
+        "qois-infrastructure": "qois-infrastructure",
+        "threema": "threema"
+      }
+    },
+    "threema": {
+      "inputs": {
+        "nixpkgs-unstable": [
+          "nixpkgs-unstable"
+        ]
+      },
+      "locked": {
+        "lastModified": 1649702331,
+        "narHash": "sha256-OsGwlWkbavEDYSWSguT8FHxJoSfo26LXhyR5Su5MokM=",
+        "ref": "HEAD",
+        "rev": "730ebce63dea4fb3eed6432b9b5dcd610e5b1de5",
+        "revCount": 1,
+        "type": "git",
+        "url": "file:///etc/nixos/defaults/threema"
+      },
+      "original": {
+        "type": "git",
+        "url": "file:///etc/nixos/defaults/threema"
       }
     }
   },
diff --git a/flake.nix b/flake.nix
index a9e0d35..7aec25c 100644
--- a/flake.nix
+++ b/flake.nix
@@ -6,14 +6,14 @@
     home-manager.url = "github:nix-community/home-manager/release-21.11";
     home-manager.inputs.nixpkgs.follows = "nixpkgs-stable";
     qois-infrastructure.url = "git+file:///etc/nixos/qois-infrastructure";
-    #threema.url = "git+file:///etc/nixos/defaults/threema";
-    #threema.inputs.nixpkgs-unstable.follows = "nixpkgs-unstable";
+    threema.url = "git+file:///etc/nixos/defaults/threema";
+    threema.inputs.nixpkgs-unstable.follows = "nixpkgs-unstable";
     fabianhauser-etaxes-sg.url = "github:fabianhauser/etaxes-sg-nix";
     fabianhauser-etaxes-sg.inputs.nixpkgs.follows = "nixpkgs-stable";
   };
 
   outputs = { self, nixpkgs-unstable, nixpkgs-stable, home-manager
-    , qois-infrastructure, fabianhauser-etaxes-sg, nixos-hardware, ...#threema, ...
+    , qois-infrastructure, fabianhauser-etaxes-sg, nixos-hardware, threema, ...
     }@inputs:
     let
       system = "x86_64-linux";
@@ -35,7 +35,7 @@
       # `nix build .#nixosConfigurations.<hostname>.config.system.build.toplevel
       nixosConfigurations = let
         sharedSpecialArgs = {
-          #threemaModules = threema.nixosModules;
+          threemaModules = threema.nixosModules;
           inherit pkgsUnstable;
 
         };
diff --git a/home/fhauser/default.nix b/home/fhauser/default.nix
index 6217fab..78ae766 100644
--- a/home/fhauser/default.nix
+++ b/home/fhauser/default.nix
@@ -1,11 +1,11 @@
-{ config, pkgs, lib, /*threemaModules,*/ nixosConfig, ... }: {
+{ config, pkgs, lib, threemaModules, nixosConfig, ... }: {
   imports = [
     ./multimedia.nix
     ./applications
     ./mimetypes.nix
     ./games.nix
 
-   # threemaModules.home
+    threemaModules.home
   ];
   home.stateVersion = nixosConfig.system.stateVersion;
   systemd.user.targets.tray = {
diff --git a/host/ochsenchopf/default.nix b/host/ochsenchopf/default.nix
index 109d2da..a75ccc4 100644
--- a/host/ochsenchopf/default.nix
+++ b/host/ochsenchopf/default.nix
@@ -1,4 +1,4 @@
-{ config, pkgs, ... }: {
+{ config, pkgs, threemaModules, ... }: {
 
   imports = [
     ./filesystems.nix
@@ -10,7 +10,7 @@
     ../../defaults/cifs-auth-fix
     ../../defaults/desktop
 
-    # TODO: threemaModules.openvpn
+    threemaModules.openvpn
   ];
 
   virtualisation = { # TODO: This should probably be somewhere else.