EL6 EE package dependencies

I've been trying to upgrade Dovecot-ee package (on EL6/x86_64) from 2.2.15.8-1 to 2.2.16.2-1. It's complaining on these two dependencies:

liblz4.so.1
libtextcat.so.0

These would both seem to be related to plugins, and don't seem to be required as package dependencies by the RPM from what I can see from the SRPM.

Anyone know what packages I need to satisfy these dependencies?