Official X7 beta firmware (Android 5.1) download and discussion-- FW3.1.5_beta - General Discussion - FiiO Forums
The following changes and improvements have been made to FW3.1.5beta compared to FW3.1.4beta

1. Fixed issue where some third-party music apps could not save downloads to the external SD cards;
2. Added album art display in lock screen.
3. Improved issue where the title of some tracks was displayed incorrectly;
4. Improved the track sorting method;
5. Improved issue where FiiO Music would exit abnormally when scanning some CUE sheets.

Beta期間長いですね
FiiO X5 3rd発売したらBetaが取れるのかな?