Reportedly arriving this week Motorola Droid 4 software update build 6.13.219 is now available. The update is pushing out from Verizon to Droid 4 owners over the air (OTA). To check if you are on the latest version or not go into Settings > About phone > System updates.
The file of this new build is 17.5MB in size which is more a maintenance update to bring stability and fixes to the handset, but it also adds a new MOTOCAST widget, improves battery life and a better keyboard backlighting management.
If you dont know how to update, Verizon’s comprehensive PDF file containting all the instructions should help.