On April 25th, Aion EU is going to merge its eight servers down to four, creating one German, one English, one French, and one Polish server. Gameforge did give itself some wiggle room and warned of the possibility of a date change.
Players on affected servers can choose to transfer their characters to a specific shard through May 15th. Aion is planning to hand out relocation gifts to all players, including a greater minion contract and 30 days of hanging with a white tiger.
In addition to the announcement, there’s a more in-depth FAQ that answers specific questions.