Can I use Microsoft ActiveSync 3.8 or ActiveSync 4.1 technology to install Communicator Mobile (2007 release) on my device?
No. Microsoft ActiveSync® 4.2, ActiveSync 4.5 or Windows Mobile Device Center 6 technology is required. If you use an earlier version of ActiveSync, you will receive an error message indicating that Application Manager cannot install Communicator Mobile because of an invalid setup file. See the Microsoft Office Communicator Mobile (2007 Release) Planning and Deployment Guide for more information about installing Communicator Mobile. You can download ActiveSync 4.2 from http://r.office.microsoft.com/r/rlidCoMo2?p1=DL_activesync42&p2=FAQ. You can download ActiveSync 4.5 from http://r.office.microsoft.com/r/rlidCoMo2?p1=DL_activesync45&p2=FAQ. You can download Windows Mobile Device Center 6 from http://r.office.microsoft.com/r/rlidCoMo2?p1=DL_WMDC6&p2=FAQ.