In a 'Windows OS' you have to set up a policy to completely stop any update as per image below. I added the image just in case someone using Windows OS find this question.

So you would need to know how to do the same in MAC.

TRy this in Thunderbird: Menu icon > Preferences/ General Scroll to bottom and click on 'Config Editor' Accept warning

Set the following: app.update.enabled = False app.update.auto = false

app.update.silent = true (will not show you reminder message when new update is available.) app.update.doorhanger = false (will not show you notifying icon or reminder message, even when a new update is available. )

Regarding policies for MAC I did find some info worth checking out: https://stackoverflow.com/questions/64980412/how-to-disable-thunderbird-auto-update Scroll way down to this section DISABLE AUTO UPDATE VIA CHANGING THUNDERBIRD UPDATE POLICIES: Then look for the sub section starting : macOS - go inside "Thunderbird.app",......

https://www.thunderbird.net/thunderbird/102.2.2/system-requirements/ macOS 10.12 macOS 10.13 macOS 10.14 macOS 10.15 macOS 11 macOS 12

macOS 10.12 (ten.twelve) is actually the minimum requirement and not 12.0