i found this on a german page for the Z9X:
Changelogs:
System
1. Added volume control for CEC.
2. Fixed the problem that the color of some special effects subtitles cannot be displayed correctly when outputting Dolby Vision.
3. Fixed the problem that some video files playback will not end automatically.
4. Modified the playback issue that some Dolby Vision films are stuterring.
5. Fixed the problem that upper and bottom black bars of some films are grayish.
Player
1. Optimized forced subtitles functions.
2. Added masked screen function.
3. Optimized the display of some interfaces.
4. Added the function to display movie info by pressing Left and Right keys for the first time.
5. Fixed the problem that the status of subtitles is abnormal after pressing subtitle shortcuts to choose subtiels.
6. Optimize playback stability.
Quick setting
1. Optimized forced subtitle settings.
2. Optimize CEC settings.
Music player
1. Optimized interface freeze problem when there are too many music files.
2. Optimized album sorting function.
3. Fixed the problem that SACD album can not skip to next song occasionally.
4. Optimized the display of some interfaces.
5. Fixed the problem that lists of artists and albums don't refresh when scanning.
6. Optimized the sorting function for the current playlist.
7. Optimized the device removal function.
8. Optimized image loading speed and stability.
9. Optimized matching function.
10. Added the loading function for artist list.
11. Optimized CUE parsing.
12. Optimized UPNP data loading speed.
13. Optimized scanning stability.
Poster wall
1. Added movie info acquisition when scanning.
2. Optimized the information icons on movie details interface.
3. Added more information in movie details interface.
4. Fixed the problem that scanning cannot be completed occasionally.
5. Optimized the loading speed of posters.
6. Optimized the poster display of watching record on the homepage.
7. Added information source on movie details interface.
8. Added function to export export collection picture in NFO.
9. Added local collection picture recognition function.
10. Optimized trailer loading.
11. Optimized custom classification collection.
12. Optimized the scanning stability.
13. Added Dolby Vision category on Widget.