[horde] Upgrade from 2.2.3 to 3.1.4

[Big Wave Dave]

All,

I have searched horde.org and google, but have been unable to find
instructions for uprading from Horde 2.2.x to 3.x.  I currently have a
very old Horde+IMP install:
* Horde: 2.2.3
* IMP: 3.2.1
* Turba: 1.1
* Kronolith: 1.1
* Mnemo: 1.1
I'm in the process of moving everything to a new machine and
refreshing all software installations.  I downloaded Horde Webmail
edition 1.0.1 which has versions:
* Horde: 3.1.4
* Imp: H3 (4.1.4)
* Ingo: H3 (1.1.3)
* Kronolith: H3 (2.1.5)
* Mnemo: H3 (2.1.1)
* Nag: H3 (2.1.3)
* Turba: H3 (2.1.4)

What is the best method for upgrading, and retaining information such
as addressbook's?  The little documentation I've found seems to
indicate you install over the top of your current version... and
update the config files.  This seems like an odd method to me, for
such a huge jump in versions.  Any guidance, links, or input is
appreciated!

Thanks,
Dave