One would think the new DirectPush technology (aka AUTD v2) were supported over a WIFI connection right? But unfortunately it isn’t so, it requires a cellular data connection such as GPRS, EDGE 3G etc. The reason behind this rather serious limitation is to be found at the device end. You see mobile devices with WIFI enabled cannot enter standby mode and receive notifications at the same time. So because DirectPush works by keeping an HTTP(S) connection alive to the Exchange Server 2003 using heartbeat intervals, the WIFI connection would have to be kept alive all the time. As some of you might know WIFI connection are quite battery hungry, so the battery would be drained in no time.
Hopefully this issue will be fixed with later models, as this reduces the usefulness of DirectPush rather drastically.