I am on 52.9.1 and it has served me well. I am considering upgrading to the latest version, only because I want to use encryption. I believe I could do that even on my current version, so I guess this is more of an experiment than anything else. There is nothing in the new version that I want or need (unless E2E and digital signing is built in). With my current set up I have the add ons I can't live without... Manually Sort Folders Minimize to Tray Adblock Plus Lightning. I don't need any third party tools to minimize Thunderbird at start up, and I don't want anything that requires manual intervention - it's a waste of time. The new addons are enigmail and GPG4Win (I'm using this on Windows 10 x64 1809 - I Have no plans to upgrade to 1909 until 2021) It seems most add ons are no longer supported in v68. Is that right? Are there 100% functionally equivalent add ons around? I also dislike the new UI, so I'll be looking to customize that to get it as close to 52.9.1's interface as possible. If I can't have all the add ons, with a user interface that at least looks half decent I'll stay on the version I'm on. I have a spare PC to test this on, so if it breaks anything it doesn't matter.