Thunderbird 60, the release version following 52, does not support Windows XP or Vista. Thunderbird 52 is the last version that supports Windows XP and Windows Vista.
Why is Thunderbird support ending for Windows XP and Vista users?
Microsoft itself ended support for Windows XP in 2014 and ended support for Windows Vista in 2017. Unsupported operating systems receive no security updates, have known exploits, and can be dangerous to use, which makes it difficult to maintain Thunderbird for those versions.
How can I get the newest features of Thunderbird?
To get the latest features and updates, you will need to upgrade your computer's operating system: