Sony Xperia Z4: specs unveiled, but only available in Japan

New flagship phone looks a lot like its predecessor, but is thinner, lighter and gets a metal frame

Sony has unveiled its new smartphone, the Xperia Z4, but has said that it will initially only be available in Japan.

The Android phone looks a lot like its predecessor, the Z3. But Sony says that the phone is thinner and lighter, and boasts improved specs.

The company has only said that the phone will be released in summer, and the announcement seems only to relate to the Japanese launch. The phone will be on display in the country this week.

The Z3 had been expected to be announced at Mobile World Congress in March, where Sony announced the Z4 tablet.

The Z4 features a full-HD screen, a Snapdragon 810 and 3GB of RAM. It comes with only 32GB of internal storage, though that can be expanded by loading it with a 128GB microSD card.

The phone comes packed with a smaller battery than some competitors, but Sony says that the Z4 will be able to run for 17 hours of talk time.

It comes running Android Lollipop, the most recent major update.