The last contact date displayed on the user information tab of an account is quite handy when troubleshooting issues. It gives you an idea if the device is still making contact to your BlackBerry Enterprise Server (BES) environment. Quite important if you are troubleshooting issues reported by the user.
However the “last contact date” does not always tell the truth. The value of the “last contact date” field seems to be stored in the user’s mailbox with other mail related statistics. If the BES has trouble opening the user’s mailbox, indicated by the user state “failed to start” on the component information tab, the value shown for last contact date may be out of date.
So if you use the value of last contact date always check the user state first to make sure the last contact date is reliable enough to base your conclusion on.