Like FireFox 15 Mozilla has released the Thunderbird 15 which also has many security fixes and improvements like support for chat that offers real-time conversation on social networks like Facebook, Twitter and a few others, it also has improvements to its Web search capabilities that was just recently added like Do Not Track technology, however even with all this added to Thunderbird 20 million+ users of the software are still left wondering about the fate of their favorite email software as they wait for Mozillaâ€™s report which is scheduled to be released some time next month.
Read the article. http://www.pcworld.com/businesscenter/article/261631/thunderbird_15_delivers_security_fixes_and_chat_support.html#tk.rss_news
Hopefully, they'll be able to use it for years, regardless - they just won't have version-numbers clicking past like roadsigns at light-speed.
I have never used Thunderbird, but just downloaded it to test it out.