If you find the real executable for the new perl, and execute that with option -v (or -V) you should see the expected info for that version. The actual executables may be named perl5.8.5 and perl5.8.6 and someone made a soft link so that perl referred to the original version. You can, of course, make a new such link. (It's possible that something else is going on, but I'll bet the aforementioned is the situation.)
chas
(Update: I notice that your original question no longer appears - it seems to have changed into the same thing as your first reply to one of the answers. This may confuse people looking at this thread...
It is possible that the new perl version is in a location that is not in your path. In any case, you can just use the new version by calling the executable explicitly. You could also make a soft link to the new version and make sure it is in your path. (Are you really sure there isn't such a link *somewhere* in your path already?)