Can I open an older base already? Or convert it automatically somehow?
My old base is so huge and so huge mess at the same time but nevertheless I can't even think about starting its all again. If there would be no way to convert/open the old base in the new soft I most probably will stay with the old one. Till a huge fire or something would destroy all the old base and backup dvds at least.
There is a converter for IM3 databases to Im5.
database-> database tools-> database converter.
I know RTFM does not sound very friendly, but it IS really a very fine manual that comes with IM5.
It has an entire section on migrating from IM3 to IM5 called IMatch 3 to IMatch 5 Migration Guide
Please read it, if you encounter problems this community is the place to go.
If you have a huge database it may be wise to start with a subset of the database just to try it and get a feeling of what IM5 is capable of before you start with the real database with the real mess.
As IM5 is still in beta please work only with a COPY of your precious images!