When Ice Cream Sandwich was first Leaked to the Droid 4 many eager modders rushed to install the Leaked version of ICS. Many knew that they would be taken off of Verizon's official OTA upgrade path indefinitely. Pretty soon Verizon began to roll out the official build of ICS and many D4 users were left stranded. Developer "Jsnweitzel" has created a solution. He added the ability to jump from any ics leak to the official ics build to his Droid 4 Utility. The process is really pretty simple you just download the OTA 6.16.217.zip file and place it on your external sdcard (if you don't have an external sdcard you can place this file along with the included crc file to your system/cache folder), Open the Droid 4 Utility and select option 9 to run the jump script, Once it does its thing the phone will reboot, then you just boot into stock recovery and flash the official update! Pretty easy stuff.
Check out the DF thread here