[tomer953]

The version you installed is the stable version, the versions you hear mentioned are the development builds and you can find it by going onto tomers github that is in their signature, or here. Just click on download zip and install the zip like you would any other addon. Be warned that this is a work in progress and while usually pretty reliable it can have problems.

No, not true.
version 1.6.1 is the latest version for Kodi 15.
version 3.0.0 is in the offical repo already for Kodi 16.

DO NOT install any version after 1.6.1 on Kodi 15, it just won't fit.
and, DO NOT install the zip from github directly from Kodi - it will install the addon in "-master" folder, which will cause you to duplicate addons, and multiple instances and dozen of bugs. I mentioned it in this thread before.

Thank you for your replies. Does this mean that I have version 15 of Kodi? How do I check which version I have?

IIRC, Settings -> System Info -> you'll see in the bottom of the skin the full version name.. KODI 15.2 or something like this...
please download the latest version from kodi.tv. Kodi 15 (Isengard) is belong to the past
if you don't sure, backup your system first.