Version numbers used by the products on this site are not decimals
*: they follow the scheme
<version>.
<revision>
Thus, 2.10 is not the same as 2.1: the latest MP3 Cat is version 2, revision 10. The previous one was actually 2.9.
* it would be too boring if everyone followed this rule: some people really use them as they were decimals or even marketing tools

There's a quite
long article on several versioning schemes on Wikipedia for the most curious ones.