On my ancient iMac (10.9.5) I use Thunderbird (78.13.0) for email. I run three different Gmail accounts with it. I got a notice the other day from Google warning two of those accounts will no longer work unless they start using OAuth2 for authentication by the end of May. The latest Thunderbird release will do the conversion automagically for you, but my old system isn't supported.
So, how might a fella make the change manually? In the Thunderbird prefs, I see OAuth2 is available as an Authentication option. Is making the change as simple as selecting OAuth2 in Thunderbird (and probably in my prefs over on the Gmail site?) Or, are there other settings that will need to be adjusted? For instance, the two accounts I need to change are both POP accounts (they're old and I didn't need IMAP when I set them up. Still don't) but OAuth2 is available in the Thunderbird settings, so I guess it doesn't matter?