Yoshiro says that Sony must update certain models every six months in order to "maintain a flagship." He added that using a yearly release cycle would make it impossible for the Japanese manufacturer to catch up with the competition. Sony also plans on continued use of the OmniBalance design that debuted with the Sony Xperia Z and has been employed for the Sony Xperia Z1 and Sony Xperia Z2.
So circle August on your calendar. That is when we should see Sony taking the wraps off of the Sony Xperia Z3.
Thanks, Anonymous Tipster!
source: XperiaBlog via Impress (translated)