[Dovecot] A few questions on shared folders

I'm looking at the possibility of using shared folders to solve a particular problem for my employer and I have a few questions:

1) Can shared folders be in mbox format while allowing the user's mail to be 
     in maildir format? (I think the answer is yes, but wanted to check).

2) What version of dovecot should I be running in order to support shared folders?

3) Is there a good overview document that people could recommend I read that 
     describes how best to set up shared folders under dovecot (and perhaps also
     gives an overview of shared folder usage in IMAP mail clients in general)?

Thanks very much,

Michael Durket