Well Johnny's net had a lot to update with in the latest update, not only does Hey! Say! JUMP now have an album section in their discography section (though no complete track listing is up yet) they have the dates for this year's PLAYZONE.
This year's production will star Imai Tsubasa with Tomoyuki Yara, A.B.C.-Z, Morimoto Shintarou, They Budou, M.A.D., Johnny's Jrs with special appearances by Nakayama Yuma. The Tokyo run will be from July 9th to August 1st and then it will have an Osaka run from August 14th to August 22nd.
Of course seeing the cast list does raise some questions as Summary runs from July 19th to August 29th so it overlaps the PLAYZONE dates. I'm sure Yara, They Budou, M.A.D. and most likely A.B.C.-Z will be PLAYZONE only and forgo any Summary appearance but I can't imagine Summary without any MoriShin and Yuma. Though as Yuma is only down for special appearances they could have him go back and forth while PLAYZONE is in Tokyo and if MoriShin's part is small enough they can do the same for him. Of course once it goes to Osaka they lose that option so it will be interesting to see if those two go with PLAYZONE there or get replaced with Kansai Juniors so they can do Summary. I guess things won't clear up on this matter until Summary starts up on July 19th.
But I guess it can be guessed that it will be mainly the younger Juniors with Hey! Say! JUMP at Summary. The older groups (minus Question? though who knows where they will end up with all the summer concerts) will be busy with other productions as not only do you have those doing PLAYZONE but Kis-My-Ft2 will be with KAT-TUN for their world tour so they won't be at Summary either. So I think for Junior groups for Summary it will be B.I. Shadow, Mis Snow Man, Hip Hop Jump and if Johnny's wants it Snow Prince Gasshoudan though they could just as easily create a new group or two with Summary this year for those younger Juniors. Either way it looks like it's a good summer for the Juniors as they will be busy for so much of it.