MIUI 7 v5.11.12 is now here for Infinix X551 16+1
Download below and flash using normal procedure and contact me in case of anything
Full Changelog
Fix - Sometimes Internet calls could not be made in 2G network (11-10)
[Contacts]
Fix - Mi Cloud namecard contacts were not included in Mi Account contacts (11-11)
[Lockscreen, Status Bar, Notification Bar]
Optimization - No service icon in status bar (11-06)
Optimization - Lockscreen camera shortcut is hidden in Child mode (11-06)
Optimization - Support changing wallpaper from top right corner in lockscreen when daily lockscreen is enabled (11-09)
[Home screen]
Optimization - Icons' names shadow effect when using light colored wallpapers (11-09)
[Gallery]
Fix - Random FC error when scanning shared albums (11-10)
[Music]
Optimization - ‘Discover’ page updates online music resources more timely (11-10)
Optimization - Support choosing from several modes when playing with car bluetooth (11-10)
[Backup]
New - Added Transfer feature to help move data from an old Mi device to a new one (11-10)
[Market]
New - Similar searching key words will display in search result page (11-10)
Fix - App language did not change with system language (11-10)
Fix - The prompt said 'icon did not show' when search result was empty (11-10)
Fix - Home screen perfect icons did not update after updating the app in third party app store(s) (11-10)
Fix - Start page tabs were misaligned in some devices (11-10)
[File Explorer]
New - Support adding folders to private folder (11-09)
New - Allow selecting restore path when disabling private settings (11-09)
[Video]
Fix - FC error (11-11)