You see this https://imapsync.lamiral.info/ ? It's only for mails but it's a great solution. Source: 7 months ago

Do your parents have a domain, or are they just using the provider's domain? I've set up my 1522+ to backup our mail accounts using MailPlus on the Synology, and IMAPSYC running on my lab server. But it's backup only, not archiving. That technology could be used to get to your desired state, but there's some work involved to make a secure connection from the internet to your Synology possible, sync/archive... Source: 7 months ago

Check out imapsync (https://imapsync.lamiral.info/) - I am using it since years and migrated tousands of mailboxes without any problems. Source: 12 months ago

I would use https://imapsync.lamiral.info/ for email and sure there is another tool for contacts and calenders. Source: about 1 year ago

There are two solutions for this 1. Using a tool called imap-sync to sync all your emails (it has a great incremental sync). You can run it periodically via cron 2. Using the same or similar tool and export to a database. Source: about 1 year ago

I'll update this if I find more. For now, this seems to be a partial solution. It's a Gmail add on (except I don't use Gmail) that adds reminders. The options when setting reminders include cancelling it if someone replies, and to remind everyone in the thread. If you combine those two, it seems like — if you use Gmail's web client and have $23/month you're dying to get rid of — a decent way to add the feature. Source: over 1 year ago