Can't synochronise below 3.7 😱

Operating system

macOS

Joplin version

3.5.6

Desktop version info

Joplin 3.5.6 (prod, darwin)

Device: darwin, Intel(R) Core(TM) i5-4288U CPU @ 2.60GHz
Client ID: de2b8c2111a945c489f10346b29dc229
Sync Version: 3
Profile Version: 49
Keychain Supported: Yes
Alternative instance ID: -

Revision: ffb3276

Backup: 1.4.3
Freehand Drawing: 3.1.0

Sync target

Joplin Server

What issue do you have?

I have an older Intel Macbook which I can no longer upgrade beyond OS 11 (Big Sur). I just brought it back to life after a bit of a vacation deep in one of my drawers. I was shocked to see that I can't synchronise my local notebooks with the server!!!

What are my options? Surely I've not now been locked out of what was very useful functionality, right?

You can use the web app to access it on your Mac. You'll need to self host it though