Packages for 3.4.0rc1 are available; sources lines are below. However, debianized source and binary packages for kdepim (KMail
, KAddressbook, KNotes, etc.) and a few others are missing. The old version of KMail at least doesn't work with the new 3.4.0rc1 libs.
I'm sticking with 3.3.2 for now, personally. I didn't really notice anything too exciting when I installed the 3.4.0rc1 packages, but TBH I didn't spend a lot of time poking around after discovering that I couldn't use KMail.