I got left behind in versions...

I'm running Gallery 2.0 RC1, which is very old.

1. What new features am I missing out on?

2. What security issues does this version raise?

3. VERY IMPORTANT -> Can I upgrade to the newest version without losing any current settings, layout, etc?

4. Version 2.0 RC1 does not run well with PHP5, so it is on PHP4, running perfectly. Does the newest version run on PHP5 correctly?

THANK YOU!