11. How to upgrade the M15?
The M15 supports online upgrade. If a new firmware is available and detected (with the M15 connected to Internet), you will find the update notification in the notification center. Then you can tap on it to enter the update menu for online upgrading. If there's no update notification found, you can open the "Technical Support" app, enter the "Firmware Update" menu, then tap the "Check for updates" icon to check manually.
Also, the M15 can be upgraded locally using firmware package: Download the firmware file from FiiO website(click here) then copy the firmware package file to the micro SD card; Open "Technical Support" app on the M15, enter the "Firmware Update" menu, and select the firmware package file to upgrade.