By this point, everyone knows that the Xperia Z3+ was just an incremental upgrade compared to its predecessor. The name actually suggests just that, while one might argue that there wasn't much of a difference from previous generations of Sony devices to the next one, let's say the Xperia Z2 to the Xperia Z3, both looking similar with the OmniBalance design and their specs were almost the same, there were enough changes in the hardware that Sony used a different name for the two. That's not the case for the Xperia Z3+ (except in Japan) which keeps the same number and is differentiated by a plus sign. While this new phone brings some welcome additions, one of the most relevant changes was in the processor, switching to the newer and more powerful but no less controversial Qualcomm Snapdragon 810. Actually, the first Sony device to use this new processor was the Xperia Z4 Tablet, which has recently become available in some regions. Both of this devices use a more recent version of the processor called v2.1, which supposedly addressed the overheating issues that some of the earlier units had.
Recent reports, however, mention that the temperature of the devices indeed gets too high when running some intensive apps, including the camera or watching some HD video, so they stop in order to prevent temperature getting even higher. Sony has responded to this issue by saying that this behavior is normal but that an update will be released in the summer to fix it. Now, an update has been certified for these two devices with build number 28.0.A.7.24 instead of the 28.0.A.6.8 that they currently use. There is no information on what will be included in the update, but since the Xperia Z3+ and the Xperia Z4 Tablet use the same processor, it might as well be the one promised by the company to fix the overheating problem. There's also no way of knowing when will the update be released, but since there are still some days before the summer starts, Sony would probably want to release it as soon as possible.