Version 68 is available for download here https://archive.mozilla.org/pub/thunderbird/releases/68.10.0/

You don't HAVE TO use v78.

tried the latest... no good. tried the 32bit version. no good. tried beta. no good. downgraded versions... no good

still ports and emails and passwords are ok. but keeps saying connection reset

Try a new profile. If issue persists, then something else is the problem and not Thunderbird updates. Which antivirus/firewall programs do you use. Are you using a VPN?

ok, a lot of headbanging later, its the settings. i tried downgrading again to an older version. nothing. paused and exited the KSOS. nothing. deleted profile. setup - new one. nothing. (god, it takes for ever to index.....) finally tried one little thing. the very basics. no antivirus, no firewalls, filters, nothing. just logging in from a totally unsecure location.

guess what, with port 110, connection security to none and password insecure it WORKS!

after that, tried re - configuring the settings step by step to see where it crashes. even did a total system reboot in between to be sure. so now, i have all the goodies i had before MINUS the incoming security. the antivirus is up and running, spam as well. i can even get ssl/tsl or starttls for my smtp at a standard port. the incoming is set as pop and connection security to none and insecure password. any other combination for the incoming mail leads to a connection reset. no matter what i try. which is funny because the backup i keep in another computer has v68.10 installed and works with encryption. set to use ssl with no problems....

Migrate a copy of the working v68 profile to the troubled pc, with a clean install of v68.

no chance of getting a newer version to work with ssl?

V78 is working just fine with SSL. I honestly don't know why it's not working for you, even on a new profile!? That strongly suggests something else is interfering with that connection, an external setup and not a problem with Thunderbird. Who is your email service provider?