On December 9th, the delayed OVA adaptation of manga side story "Ilse's Journal" will be packaged with Attack on Titan's volume 12. The manga followed the Scouting Legion member who is the only member of her squad to survive a titan attack, only to meet another titan with her horese dead and gear damaged.
A retailer is now saying that volume 13, due out April 9th, will also be packaged with a new anime episode.
In other AoT manga doings, the first Before the Fall prequel
on the cover of Gekkan Shônen Sirius