diff --git a/cluster/services/storage/default.nix b/cluster/services/storage/default.nix
index c2a5a7a..615bb73 100644
--- a/cluster/services/storage/default.nix
+++ b/cluster/services/storage/default.nix
@@ -19,8 +19,14 @@ in
       garageExternal = [ "grail" "prophet" ];
     };
     nixos = {
-      external = [ ./external.nix ];
-      heresy = [ ./heresy.nix ];
+      external = [
+        ./external.nix
+        ./s3ql-upgrades.nix
+      ];
+      heresy = [
+        ./heresy.nix
+        ./s3ql-upgrades.nix
+      ];
       garage = [
         ./garage.nix
         ./garage-options.nix
diff --git a/cluster/services/storage/s3ql-upgrades.nix b/cluster/services/storage/s3ql-upgrades.nix
new file mode 100644
index 0000000..a020d17
--- /dev/null
+++ b/cluster/services/storage/s3ql-upgrades.nix
@@ -0,0 +1,12 @@
+{ config, lib, ... }:
+
+{
+  system.ascensions = lib.mapAttrs' (name: fs: {
+    name = "s3ql-${name}";
+    value = {
+      requiredBy = [ "${fs.unitName}.service" ];
+      before = [ "${fs.unitName}.service" ];
+      incantations = i: [ ];
+    };
+  }) config.services.external-storage.fileSystems;
+}