You can always upgrade Joomla! from 1.6.2 to 1.6.3 using my free
Admin Tools Core
. It only takes 7 seconds to go from 1.6.2 to 1.6.3 (Sorry for the self-plug). So far I have not bumped into any loss of functionality with 1.6.3, but I'm only using it for testing my own extensions and haven't spent more than an hour on it today.