offlineimap VS tailscale

There are also isync and OfflineIMAP which sync email locally.

I'd consider using the Bridge + offlineimap (or a similar tool). That can connect via IMAP to both the Bridge IMAP and your destination IMAP service and copy all mails automatically that way.

As u/alex_herrero says, Proton Mail Bridge is very much useful. I'm using this myself together with offlineimap to have a local backup. I also use the Bridge with Thunderbird too, which also works quite well (especially the v3 beta).

For the sync / import functionality the MSP uses offlineimap, which is another counterpart to IMAPSYNC. Changing the import tool will not bring up the solution to the main problem, that I am not able to reset the imported stuff back to zero in order to test the different scenarios of the main use case.

Don't risk relying on someone else's hardware or service, use something like Offlineimap or Mbsync to sync your emails to your computer then automate multiple backups.

Many people use OfflineIMAP.

I've used offlineimap in the past: http://www.offlineimap.org/

I'm looking into replacing Thunderbird with mu4e (for the first time, despite being an Emacs guy for 15 years) and I got unexpectedly stuck at step 1, dowloading my email. offlineimap is broken on newer Pythons, getmail doesn't support Python 3 at all, and fetchmail is infamously inscrutable. It all seems a bit ridiculous, but I guess it speaks to how webmail has come to dominate proper email clients. Any recommendations?

Neither a mutt, nor an offlineimap user, but I believe those two are often used in combination: http://www.offlineimap.org/

Tailscale - Built on WireGuard. Easy to use. Control server is closed source. Client code available with a BSD3 license + separate patents file.

Tailscale

I'm using the GitHub version of tailscaled on one of my Macs as a background daemon launched at boot. To upgrade to the latest version, try the following:

Tailscale is a VPN service that makes the devices and applications you own accessible anywhere in the world, securely and effortlessly. It enables encrypted point-to-point connections using the open source WireGuard® protocol, which means only devices on your private network can communicate with each other.

Might be possible to do using a VPN as long as you can get broadcast/multicast packets forwarded.

Tailscale unfortunately doesn't support it...yet?

https://github.com/tailscale/tailscale/issues/1013

Tailscale - Make depaware output patch compatible

Tailscale is another way of doing it. I'm using it to access my Pi's Samba shares from my phone but it works from Windows as well.