diff --git a/nixos/modules/services/web-apps/nextcloud.nix b/nixos/modules/services/web-apps/nextcloud.nix
index 9de2fbc07328f0..5f6f2bc7a16db3 100644
--- a/nixos/modules/services/web-apps/nextcloud.nix
+++ b/nixos/modules/services/web-apps/nextcloud.nix
@@ -322,12 +322,21 @@ in {
           Please migrate your configuration to config.services.nextcloud.poolSettings.
         '')
         ++ (optional (versionOlder cfg.package.version "18") ''
+          A legacy Nextcloud install (from before NixOS 20.03) may be installed.
+
           You're currently deploying an older version of Nextcloud. This may be needed
-          since Nextcloud doesn't allow major version upgrades across multiple versions (i.e. an
-          upgrade from 16 is possible to 17, but not to 18).
+          since Nextcloud doesn't allow major version upgrades that skip multiple
+          versions (i.e. an upgrade from 16 is possible to 17, but not 16 to 18).
+
+          It is assumed that Nextcloud will be upgraded from version 16 to 17.
+
+           * If this is a fresh install, there will be no upgrade to do now.
+
+           * If this server already had Nextcloud installed, first deploy this to your
+             server, and wait until the upgrade to 17 is finished.
 
-          Please deploy this to your server and wait until the migration is finished. After
-          that you can deploy to the latest Nextcloud version available.
+          Then, set `services.nextcloud.package` to `pkgs.nextcloud18` to upgrade to
+          Nextcloud version 18.
         '');
 
       services.nextcloud.package = with pkgs;