Update over USB or SD card for the latest firmware from Pioneer for its connected head units
The changelog notes a fix for a popping sound when playing music from an SD card. And, of course, various other bugfixes. Nothing major here, but it's always great to see a firmware update released.
Be sure to read the update instructions, and make sure you get the right file version for your head unit. And a quick note, the SD card you're using to update the device has to be formatted as FAT32.