Wow, Dark Horse are really getting ahead on their Avatar products, The Rift Part 2 is not even out yet and now we have the cover and release date for the Hardcover collection.
Unfortunately, the original source for this news is a bit up in the air, but this is clearly proper news.
As best I can find the source for the cover is
http://images.abovethetreeline.com/ea/RH/images/jacket_covers/original/9781616555504_7d878.jpg
but I cannot actually go to the homepage of this site and find this image or the full details of where the release date is stated.
Other sites are reporting that the release date is February 24th 2015 which is a Tuesday, meaning that the comic store date would be February 11th 2015.
The date makes sense as it does fit in well with when the other hardcovers came out after the third part of the series.
I love this cover, Team Gurihiru always do great work on these library edition covers and this is no exception. Aang, Toph and the mysterious spirit in the background, very fitting. I would have maybe expected YangChen to be on the cover, but this is fine as is.
As ever expect the book to have annotations and a concept art section like previous hardcovers.