Due to persisting game issues and Battlelog instability, DICE delayed their Battlefield 4 Double XP event until the team can resolve the issues.
The Double XP event, held from Premium members, was delayed after disappearing statistics and general connectivity issues forced DICE to seek a later date. "The end of December 2XP event for Premium members has been postponed and will be run at a later date. Stay tuned for more information. We apologize for the inconvenience."
After more than two months of reported issues and bugs, DICE suspended all future projects, including all DLC, until the team can resolve all existing issues. DICE also delayed the PC Mantle patch to sometime during this month.
You can track the status of all existing issues on the Battlefield 4 forum.