Since the arrival of the Xperia Z Sony has made plenty of noise about the environmental protection it has built into it's phones and tablets. It appears that the company is now rather less sure about water resistance in particular and is now advising against using its devices underwater.
Given that a large part of its message has been that the Xperia Z series is a great underwater camera, and that cleaning your device under a running tap is something you can do without worry, this new advice is less than welcome.
I've used both the Z1 and Z3 Compact as underwater cameras without any problems. (That's also true of the Samsung Galaxy S5 by the way) However Sony has clearly found that there has been an unacceptable level of failure due to water ingress and is now seeking to reduce its liability.
Given the big budget advertising campaigns that heralded water-proofing, Song should remain liable for water ingress issues until it has shown that it has made a significant effort to contact owners and make them aware of the change of advice.