Load balancing Exchange CAS traffic from single source(s)

If you're at 2012_04_06, you're actually two revisions back; that was superseded by 2012_06_08 and subsequently by version 1.2 (we switched numbering schemes).

If at all possible, please install and upgrade to a newer version; alternately, deploy using the new version on a separate IP address and test some clients using an entry in the local 'hosts' file or something similar. When you're satisfied that the new version works according to your plan, you can either swap IP addresses or change DNS entries to point to the new IP address(es).

Please open a support case if you run into any difficulties, this does not resolve the situation you're seeing, or you simply want assistance in installing and using the new iApp. (However, the Deployment Guide is fairly detailed on how to use it.)