We last saw me sailing the good ship macBook Pro mid-2014 (Aka: MegaDoDo) to Catalina a good twenty days ago.
Not much has changed in the last twenty days other than a few products releasing updates and Apple releasing the first of what are bound to multiple updates.
Today was the the day I decided it wasn't worth putting it off any longer, I would perform a full image backup, install Catalina and go about fixing up my development environment - which Apple's installers tend to break every major upgrade.
Yesterday I took a new 64GB SanDisk USB stick, formatted it as an APFS Volume, added two extra volumes and installed Majove on one and Catalina on the other. If needed, I can boot my machine using a Mojave system.
Next was the full image backup. I use SuperDuper who are currently in beta with a Catalina version. I have been testing it on Mojave and ran into an issue today. I reported it to them and even though it's a Sunday morning, half an hour later I got a pre-release version in the mail. I really like their level of support.
Full backup image complete I ran the installer and went to lunch.
An hour or so of upgrading later my machine finally came back up. Initial thoughts, it's definitely faster. Whether this is just the fresh system install syndrome where all the caches and b-trees are empty I don't know. We'll see.
Amazingly Apple didn't destroy my development setup. They upgraded my PHP but this time didn't blow away my configuration files or /usr/local, /usr/opt etc. They did move some of the stuff in the root of the volume as that is now read-only. I really wish this was an option you could turn off. I diff'd the new default php.ini and php-fpm.conf files with my existing ones to make sure I inherited any new configs and everything run great. All my local development sites work as expected.
Everything that I have tried seems to work just fine. I had to re-install brew, which was simple. Arq Cloud Backup seems broken although the main Arq product works OK.
All in all quite a painless upgrade, quite possibly because of all the advanced planning I put into it.
Sadly they finally killed the Widgets (F12) and also killed the "Find my Friends" in the "Today" sidebar. Sure they have the new "Find My" app, but it's not the same.
So far so good. If you upgrade, your milage may vary. Unless you use very specialized software, you'll probably have no difficulties at all.
*Photo care of Apple, Inc.