When was glass rear screen introduced?

[BentleyJava]

Hi all,

First post, started looking for a Boxster after driving a colleagues. Currently have a TT and ready to move on.

First off, What year did Porsche introduce the glass rear screen?
Also (and I've run a few searches) is there anywhere I can find information on what spec changes there were year to year?

Thanks so much, hope to be a frequent participant here!

-Adam