iPhone Calendar no longer syncs with Mac and vice versa!
I have been syncing my iPhone with my Macbook Pro peer-to-peer for ages (i.e. not using iCloud). These are not Outlook calendars or anything server/network related, just locally created calendars.
Since I upgraded to OS X Ventura, calendars of any kind no longer sync between the devices. The syncing process seems to go through the motions, but the calendars on the iPhone and the Mac don't update with each other's events. (Music files seems to sync fine, FWIW).
Since applying the security update to OS X 13.4 this week, a new message appears in the Finder iPhone window under 'Info' saying "iPhone is syncing Calendars over the air" and "Over-the-air sync settings can be changed on your iPhone."
I've looked on my phone, but I can't see anywhere that I can change these mysterious settings. I've no idea what it means, but it's not something that I have changed manually. I don't have an iCloud account and never have done and I don't want one. I just want to be able to sync my calendars locally between the Mac and iPhone like I've been doing for years. I've tried creating new calendars on the phone and Mac, but these aren't recognised across the devices either.
Any suggestions for getting this working again would be great.
Thanks!
(If the ability to sync locally has been removed, it would be nice if Apple let us know.)
iPhone 12 mini