Sony Xperia Z3 and Z2 Android 5.0 Lollipop (Android L) update is rolling out, while there are signs indicating the Xperia Z4 development is continuing as scheduled.

In a Tweet on Tuesday, April 7, Sony announced that Android 5.0 Lollipop is rolling to both the Xperia Z2 and Xperia Z2 Tablet. The same message also reminded users that all rollouts come in phases. In other words, users will be notified automatically as soon as their updates are ready for download. Naturally, owners with unlocked devices may get their updates sooner. Those using phones under contract will need to wait for announcements from their wireless service providers.  

For now, the Xperia Z3 rollout is pending even though Sony has already confirmed that the device will be getting Android 5.0. Even so, the rollout may start anytime in the weeks ahead. Besides the Xperia Z3, the Xperia Z3 Compact and Xperia Z3 Tablet Compact will also get the Android 5.0 Lollipop update.

Meanwhile, the tech gossip mill has been abuzz with discussion over purported Xperia Z4 photo leaks. One leak that allegedly shows the device cover was originally posted in early April on Polish-site, Galaktyczny. Based on the images, it would seem that the Xperia Z4 is going to share the same physical appearance as the Z3. However, there is a cutout for a microUSB port on the bottom of the device.

Another leak showing the user-interface made the rounds over at Softpedia in the same month as the Galaktyczny leak. Based on Softpedia's information, the Xperia Z4 appears to have a 5.1-inch full HD (1080p) touchscreen. The photo set also reportedly shows a 20.7 MP camera on the back of the mystery device.

This has not, however, stopped the rumor mill from considering the possibility of other variants of the Xperia Z4. The more recent rumor suggests that Sony is working on the Xperia Z4 Ultra, which is the beefed-up version of the Xperia Z4. This idea was first hinted at in a recent report by Phone Arena, which in-turn based its theory on alleged leaks from Taiwanese publication Digitimes.

According to other rumor sites, the Xperia Z4 may be revealed later this year. This assumption is based on the the Xperia Z3 and Z2 being released in 2014. The first generation Xperia Z1 was launched just one year prior. Should Sony continue with its usual launch cycle, this speculation may actually come true. Or, the tech giant might hold back on releasing its newest flagship for another year.

Not surprising, there is no official reference for the Xperia Z4. Sony has neither denied nor confirmed the existence of the long-rumored successor to the Xperia Z3. For now, the Xperia Z4 exists in the wishful imagination of the overactive tech rumor mill.