Will the IT policy gets changed when we upgrade the BES server from 4.0 to 4.1.4. Is there any precaution we can take regarding this...

Is the 4.1.4 version DST approved.

Regards

The IT Policy will get repushed to all devices, new default policy settings will be pushed for settings that didn't previously exist (like phone call logging).

Are you at 4.0 with no service pack? I believe 4.0 SP3 or above is required for the upgrade you're doing. Yes 4.1.4 is DST Ready ... but you also need to make sure your HHs are too with their OS.