Sony Corp. unveiled the latest version of its flagship smartphone on Monday, with the product set to debut in Japan this summer.

The new Xperia Z4, which is the upgraded model of the current flagship Xperia Z3 handset, has improved camera and digital-effect image functions.

"As we developed the Xperia Z4, we had a goal of making the utmost efforts to produce the best camera smartphones," Tomokazu Tajima, senior vice president at Sony Mobile Communications Inc., Sony's smartphone arm, told a news conference at the company's headquarters on Monday. "We think the Xperia Z4 is one form of perfect camera smartphone at this point."