Release date rumors for Sony's Xperia Z5 have recently surfaced on the web, sparking anticipation and debate amongst Xperia fans. Meanwhile, Sony is rolling out Android 5.1 Lollipop to the older Xperia Z3 and Xperia Z2 series. These developments come weeks after the Sony Xperia Z3+ began hitting the global market.

Android 5.1 Lollipop Rolling Out to Xperia Z3, Z2

On Tuesday, Sony rolled out the long-promised Android 5.1 Lollipop firmware for the Xperia Z3 and Xperia Z2. The update is also available for Xperia Z3 Compact, Xperia Z3 Tablet Compact and Xperia Z2 Tablet.

Naturally, it will take awhile before U.S. carriers start introducing Android 5.1 Lollipop to their versions of the Xperia Z3 and Xperia Z2. Wireless providers usually need to conduct extensive testing before a new operating system is rolled out to subscribers. On the other hand, users with unlocked devices will get their updates first.

Sony also plans to introduce Android 5.1 Lollipop to the Xperia Z1, Xperia Z1 Compact and Xperia Z Ultra over the coming weeks. Afterwards, the company will add Android 5.1 Lollipop to the Xperia T2 Ultra and Xperia C3. The fourth Sony rollout for Android 5.1 will reach the original Xperia Z series, Xperia M2 and Xperia M2 Aqua.

Android 5.1 Lollipop Changes for Xperia Z3, Z2

According to Sony, Android 5.1 Lollipop will bring a number of changes. These include increased customization options, new LinkedIn integration, improved camera, enhanced enterprise support and SmartWear integration.

Xperia Z5 Rumors and Speculation

In early July, Technodify reported that the Xperia Z5 will be launched alongside the Xperia Z5 Compact and Xperia Z5 Ultra. Apparently, the Xperia Z5 will debut in Japan in September.

The publication also cited a leak, which gave spec information. Apparently, the Xperia Z5 comes with the Qualcomm Snapdragon 820 processor, 4GB RAM, fingerprint scanning technology, 4K video recording and much more. However, the source of their information remains anonymous.

This report comes less than a month after Sony launched its latest Xperia Z3+ worldwide. In Japan, the Xperia Z3+ is known as the Xperia Z4. It remains to be seen whether the Japanese tech giant launch a new device just months after a major release. As always, consumers should take rumors with the proverbial grain of salt.