diff --git a/nixos/modules/rename.nix b/nixos/modules/rename.nix
index 4ae642222740..c44332237fc2 100644
--- a/nixos/modules/rename.nix
+++ b/nixos/modules/rename.nix
@@ -51,6 +51,10 @@ with lib;
     (mkRemovedOptionModule [ "services" "misc" "nzbget" "openFirewall" ] "The port used by nzbget is managed through the web interface so you should adjust your firewall rules accordingly.")
     (mkRemovedOptionModule [ "services" "prometheus" "alertmanager" "user" ] "The alertmanager service is now using systemd's DynamicUser mechanism which obviates a user setting.")
     (mkRemovedOptionModule [ "services" "prometheus" "alertmanager" "group" ] "The alertmanager service is now using systemd's DynamicUser mechanism which obviates a group setting.")
+    (mkRemovedOptionModule [ "services" "prometheus2" "alertmanagerURL" ] ''
+      Due to incompatibility, the alertmanagerURL option has been removed,
+      please use 'services.prometheus2.alertmanagers' instead.
+    '')
     (mkRenamedOptionModule [ "services" "tor" "relay" "portSpec" ] [ "services" "tor" "relay" "port" ])
     (mkRenamedOptionModule [ "services" "vmwareGuest" ] [ "virtualisation" "vmware" "guest" ])
     (mkRenamedOptionModule [ "jobs" ] [ "systemd" "services" ])