As translated by me:
① It will be held at Tokyo Dome City Hall.（Same as every year. Right now, there's no information about anywhere but Tokyo）
② The name "Summary" will cease to exist and it will be like a concert.
③ The performers will be Sexy Zone, ABC-Z, and Juniors.（Same as last year.）
④ The performance will be solos of the members of the debuted groups plus a few juniors each = Kento + some number of juniors, or that sort of thing, it seems.
I'm not sure how accurate this is. The blurb I translated comes from this blog, but very similar information is available here. I don't really know what to think of this... clearly ① and ③ sound good to me, but I'm really not sure what to make of ② and ④. ② is really perplexing to me; Johnny's has been doing Summary for so many years now... why change it?? Summary is like an institution in Johnny's, and I don't want to see it "cease to exist." The Japanese なくなる seems a bit extreme to me, it can mean "disappear" or "die" (it's a polite, euphemistic way to say someone died, like "passed away," and it can also mean disappear as in "go extinct"...), but the other site doesn't put it much more lightly; they say "サマリーと違う。"("different from Summary") bolded quite emphatically. I also don't know what to make of the "solo" thing... I feel almost as if Johnny's is forgetting about how it succeeded (through group dynamics) and is trying to be more like K-pop or AKB48 now.
But hey, this is all just rumours, so... here's to hoping it's completely false. (>___<)