I'm using Arq Backup for a couple of clients. It has an option to send an email when a backup job finishes, which is good. But I would also like to get a notification if a backup job hasn't been executed for the last X days.

Is there any app on Cloudron that can be used for this? Assign an email address, and notify me if nothing has been received in a defined timeframe?

Edit: I just realised that Arq also can execute a script after a backup, so anything that could alert based on missing pings using GET/POST etc would also work.