While having a connector would give access to everything on the Zimbra server, including shared documents and briefcase areas, one should be able to access the core features of the Zimbra server (mail, contacts, calendar) without a connector:
- Use IMAP to access the mailboxes on the server. This should provide access to shared folders, although one would have to use the web client to create new shared folders.
- Use LDAP to access the GAL (although I haven't managed to do this yet with Kontact, it should be doable).
- If Evolution supports it (I don't use it, so can't check), you should be able to access any calendars you have access to via http:// URLs to the iCal file.
- Not sure what kind of remote addressbook capabilities Evolution has.
If the Evolution connector were to die tomorrow, it's not like you'll be locked out of your Zimbra account and won't be able to use Evolution anymore (although, personally, I think everyone should switch to Kontact, but that's an argument for another day
).