The Xperia Z3+, known as Xperia Z4 in Japan, is Sony's current best offering in the smartphone market. It is considered an incremental upgrade from its predecessor, as it got very few changes in terms of the overall design and its internals were only slightly upgraded as well. The display is basically the same as it uses the same technology, size, and resolution, the main camera uses the same sensor as the last version and the amount of RAM was kept the same at 3 GB. The most noticeable changes are that the resolution of the front-facing camera was increased to 5 megapixels and the internal storage is now 32 GB, plus, the processor was upgraded to the latest version available of Qualcomm's Snapdragon high-end offering, the Snapdragon 810.
This particular processor has been object of a controversy that's still going on, it might not handle its temperature very well when running some intensive apps, even when it was found that a newer version of the processor called v2.1 is included in the handset. This situation was acknowledged by Sony and they promised to improve this aspect with a software update, which has yet to come. Some users have created videos to show that the issue is not as bad as we are led to believe, when recording 4K video, for example, the temperature was inferior to other handsets and the Xperia Z3+ was able to record more minutes of video in this resolution.
In order to prevent the phone to overheat, the device stops running some apps or it doesn't use its full potential. It can get pretty annoying to keep seeing that apps are forced to close, and while the update is expected relatively soon as they promised to release it in the Summer, there may be a few users who would like try the following solution posted in XDA Developers. What you need is a case for the phone and aluminum foil that could be found in most kitchens. The user placed six layers of foil between the back of the phone and the case, which resulted in better performance and less temperature, the only drawback is that NFC could not be used as the foil would block it. While it's not the most elegant solution, it could make the wait for the update a little better.