When Sony had originally announced the Xperia Z Ultra phablet flagship, the company had mentioned 'X-Reality for mobile' as part of the onboard software suite. X-Reality is the successor to the powerful image and video processing Bravia Engine for mobile. The reason for the delay is most probably unfinished software, but worry not, a software update which will begin rolling out on September 9 will bring X-Reality mobile engine to all Xperia Z Ultra phones, which currently include only HSPA+ models. Sony will begin selling LTE enabled Xperia Z Ultras starting September 9.
Meanwhile, a new software update for the HSPA+ Xperia Z Ultra is out. With a build date of 19 July, the update doesn't seem to do much. We believe it is just a routine bug squashing update.