[Typo3] Implementation of RSS newsfeed/tt_news version

[Kanu- und Ski-Club Lünen e.V. - Thorsten Dorn]

Hallo List,

iI would like to include a RSS newsfeed on our homepage. We have  
tt_news 1.2.3 installed, which I suppose is a too old version to work  
with pmk_rssnewsexport 0.1.4. Would it be possible to update tt_news  
to version 2.1.1. without getting in trouble with TYPO3 3.6.1?

Generally: When am I allowed to install a newer version of an  
extension? When will I get in trouble? Most extension in the online  
repository are declared for newer versions of TYPO3, but our provider  
won't update our intallation...

Thanks for answering,
Thorsten