Originally Posted by sacredsoul
The Z2 supports OTG apparently. My question is, can I move files directly from my current Android phone to my Z2 using OTG? Or Do I still have to use my PC as the middleman between the two?
You cannot directly connect two phones with a cable and transfer files. The reason is that the phone never exposes its filesystem directly, but uses an MTP client to make files available on a PC. Since the Z2 is not an MTP host, it cannot see the files on the "old" phone.
There could be an exception if your "old" phone is really old. Originally, Android phones used a FAT filesystem for the "SD card", and then often exposed that directly to PC's, and then they ought to work also with an OTG phone as host. I cannot confirm what phones from what manufacturers would work in that manner, however.
Another way to transfer files, if your old phone supports OTG, is to use a USB memory stick as intermediate storage. A PC might still be more convenient, however, compared to using a clunky file manager on yotr phones.