We've started to hear plenty rumours about Sony's next flagship, including one report which reckons the Japanese firm will return to an annual launch of its top device, ditching the recent trend of every six months, though not until after the Z4 launches.  Updates: We may not have quite as long to wait for the Sony Xperia Z4 as we'd thought, but it still probably won't launch before June.  Cut to the chase  What is it? Sony's next flagship smartphone When is it out? Sometime in the summer probably What will it cost? A lot - this will be a high-end device Sony Xperia Z4 release date  Early rumors suggested we'd see the Sony Xperia Z4 at MWC 2015, but that hasn't happened. So when will we see it? That's not entirely clear.  Some rumors suggest that Sony is moving from two flagships a year to just one and pushing the Sony Xperia Z4 back to the summer.  On the other hand Sony has already started rolling out its '4' product range with the Xperia Z4 Tablet and the Xperia M4 Aqua, so it would make sense to have a smartphone alongside them. Plus, speaking to TrustedReviews, Tim Harrison, Sony's Vice President of Global Communications and PR, claimed the company hasn't moved to a 12 month product cycle.  So maybe we won't have to wait too long after all. The Xperia Z4 Tablet isn't set to launch till June anyway, so that still gives Sony a few months to announce its next flagship and get it on the market at the same time.  What will it cost?  There's been no information on how much the Xperia Z4 will cost, however as it's a flagship smartphone (and a Sony one at that) we'd expect it to ship with a high price tag.  The Xperia Z3 launched at £549 ($630, AU$849) and we'd expect the Z4 to launch at around the same price.  Rumours have also suggested that Sony could be plotting two versions of its flagship smartphone. There would be a Z4 with a 1080 x 1920 full high definition screen, similar to the one found on the Xperia Z3. The second version would offer a much higher 1440 x 2560 (QHD) resolution.  These rumours claim that the 1080p version will cost less than the QHD version, though we'd take those claims with a pinch of salt.