After the success of the first movie, Sword Art Online: Progressive -Aria of a Starless Night-. Now Sword Art Online will release its new film in the fall of this year. The new film is titled Sword Art Online: Progressive -Scherzo of a Deep Night-. However, the release this fall is only for Japan. There is no further information when the release schedule for outside Japan.
Sword Art Online: Progressive -Scherzo of a Deep Night- will be adapted from the SAO Progressive Light Novel Volume 4 and is set around the 5th floor of Aincard.
Here's the full sypnosis from the SAO Progressive Volume 4:
It's been just two months since they were trapped in the game of death that is Sword Art Online, and Kirito and Asuna continue their struggle at the vanguard of progress through the game. The fifth floor of Aincrad is a mazelike ruin, and the two dare to take pleasure in raiding it for the treasure it contains. Upon returning to the fourth floor, it's time to do some questing on behalf of the Elf Lord Yofilis--but here begins Asuna's discontent, for in doing so they will have to face her least favorite monster ever...
Source: Yen Press
FYI, the serialization of the SAO Progressive light novel, which was written by Reki Kawahara himself, started in October 2012. The light novel series is still ongoing and currently has 8 volumes.
Here's the latest trailer Sword Aart Online: Progressive -Aria of a Starless Night-