I'm sorry, I withdraw my previous comments. I found that (for whatever reason) I had the Mozilla PPA installed, but had forgotten all about it. I did not realise I was using beta-test software.
Please ignore the following comment, see my reply below.Thunderbird 115.2.3 came down with the updates for Linux Mint 21, and it's installation has been a MAJOR disaster. It has totally wiped my calendar - all upcoming events have been deleted! The...
