16 should be out in a day or two. I don't know what themes you have, but if they work in 15 they should work with 16.

i lost 3 or 4 themes back around v13 0r v14 now in the themes menu the themes i want show up there but they are faded out and say that they are not compatible w/ my version of firefox is that a mozilla fix for compatibility or is it a designer fix

If the themes aren't being updated that is a problem you need to take up with whoever develops those theses.

You will have to check the add-ons page of the theme(s) to see if they are compatible.
There tend to be all kinds of icon and other CSS changes with each Firefox version update and those can easily break themes.