versioning is not pretty

[akb427]

Gnus versioning is confusing the heck out of me.

My platform is Ubuntu 11.10. 

So far I've determined that there can be gnus 5.10 versions that are newer than 
5.11 versions. (XEmacs version 1.93 = gnus 5.10.8, and is no older than Feb 
2009, while Ubuntu gnus version 5.11+v0.10 = No Gnus 0.9, and I think is circa 
2008). 

XEmacs just packaged 5.10.10 in June of 2012 (= XEmacs package version 1.95), 
while Gnu Emacs (in Ubuntu 11.10) ships with 5.13. 

Is XEmacs packaging massively behind Gnu Emacs packaging? Will I gain cool new 
features if I switch emacses? Or can I just download a 5.13 someplace and run 
it in XEmacs? 

Wikipedia claims 5.10 is Oort and 5.13 is No Gnus. But as I mentioned above, 
Ubuntu is shipping a 5.11 No Gnus that's older than their 5.10 version, so that 
has to be at least No Gnus, right? And Wikipedia doesn't mention Ma Gnus, which 
I gather is the current development version? Will Ma Gnus get a 5.x number on 
release? How do I download releases using bzr?