Messaging & Security Feature Pack (MSFP).
MTekk (link dead) reviews O2 Xda Atom Exec PDA phone and concludes with a great score of 9.6 out of 10 that “the Atom Exec offers most of the tools needed for the business professional in a small and light weight package. If O2 were to include an alternate PIM such as Agenda Fusion 8 or Pocket Informant Pro with the software bundle, then the Atom Exec would offer all the tools required by a business executive in this fast paced world. I have made mention of this to O2 and they are considering its feasibility. As it stands, the Atom Exec would be my pick of the devices currently reviewed if you are looking to upgrade today from an older WM2003 device, or are looking for your first Windows Mobile device to assist with your busy schedule. Current XDA Atom owners (running the latest ROM release) would find this device only a minor upgrade.”