go to Thunderbird.net and download the current version and install it would seem like the logical thing to do. When dealing with ancient versions, they is no upgrade path through 20 or so updates.

Hi I didn't know that I can install a new version over the old one without loosing any data/settings. Thanks Regards

Try this: Backup your entire profile folder first - [[https://support.mozilla.org/en-US/kb/profiles-where-thunderbird-stores-user-data|https://support.mozilla.org/en-US/kb/profiles-where-thunderbird-stores-user-data]] JUST to be Sure nothing can go wrong when upgrading. After you have a backup of your mail and settings, THEN go get this file: https://download.mozilla.org/?product=thunderbird-68.4.1-msi-SSL&os=win64&lang=en-US and run IT. Here is one more article you might want to read: https://support.mozilla.org/en-US/kb/moving-thunderbird-data-to-a-new-computer I hope this helps!