Ok still running imp 3.0 on a 5.1.2.  Was about to do the Imp 3.1 upgrade with the following RPMS from Dan Browns site:
e-smith-turba-1.1dcb-1.noarch.rpm
imp-3.1-2es.noarch.rpm
horde-2.1-1es.noarch.rpm
then 
rpm -Uvh *
came back with
error: failed dependencies:                              
        horde = 2.0 is needed by dcb-e-smith-horde-0.2-4 
        imp = 3.0 is needed by dcb-e-smith-imp-0.2-2     
Any thoughts?
My goal is to get the latest updates on whatevr I need for  Horde as I'd like to be up on imp/turba/and Kronolith...and I'm assuming php as  well on sme 5.1.2.