@stephenw10 Yes you are correct, I misunderstood myself. After my box crashed doing the 2.6.0 to 2.7.0 upgrade and eventually after getting 2.7.0 to work, I compared both xml backup files and only saw differences in time stamps, but now realise it's the import of updated packages that caused my problem.
I'm running ZFS and will look at taking an image snap once I work out how to get from Pfsense to FreeBSD, out and back via a USB3 port. That suggests I need an external monitor, keyboard, and mouse on the box, unless it can be done through Pfsense GUI, but that won't work for recovery if the GUI has crashed. I've met these situations before and an image snap can only be trusted to work if you've actually used it successfully to recover. In the PC world I've trusted and used Acronis for years. Thanks for the link. I've always created bootable flash sticks and created matching config XMLs. Once the box crashes, I'm offline with no internet access to download anything or get help asking questions. I still keep an ISP Thomson box handy just in case.
Thanks for your help - regards - Vox