Incoming calls may be routed to voice mail if Sophos Mobile Security for Windows Mobile is downloading files when the call is received.
If Sophos Mobile Security for Windows Mobile is downloading files in the course of an update, and the mobile phone receives an incoming call, that call will be routed to voice mail (if available) or declined.
This is consistent with the behavior of other applications which download files via GPRS. For example, if Internet Explorer is downloading a file via GPRS, and a call comes in, that call will also be routed to voice mail (if available) or declined.