Along with Firefox 184.108.40.206, Thunderbird 220.127.116.11 has been released as well. The release notes for Thunderbird are a bit brief:
- Improvements to product stability.
- Several security fixes.
The Mozilla and OSU OpenSource Labs FTP Servers appear to be overload at this time but you should be able to download Thunderbird 18.104.22.168 directly from the product page. Most users should be able to upgrade Thunderbird (if it hasn’t told you to do so already) as well as Firefox by going to the Help menu and selecting ‘Check For Updates…’