*Upgrades my general 'when is it out?' status from 'soon' to 'very soon'.
Are you still on 4.5.6 as stated in your profile? I highly suggest that you step through 4.5.11 first.
4.5.11 & 5.0.2 Released!
There were lots of LDAP & Tomcat changes made after 4.5.6, and while we test everything, just by very nature you're going to get more 4.5.10/.11 > 5.0.2 'tests'. ie: More users making that jump path because they were on 4.5.9/.10/.11 when they switched to 5.0.x
Don't know if you do, but if you have a LDAP replicas we highly advise at least 4.5.10 first, and better still is 4.5.11 see:
LDAP Replicas 4.5.x to 5.0.x - Zimbra :: Wiki