[Contacts]
Optimization – Simplified display method of WeChat/Google+ accounts

etc. in contacts detail page
Optimization – Set QQ as default IM when adding a new contact
Optimization – When sending contacts information using SMS, the

contact's recently used number will be marked
Fix – Sometimes, opening unnamed contacts would cause app to FC
Fix – Some characters blurred in the add new contact page
Fix – Form error in contacts settings page
Fix – Call logs could be seen in Guest mode
Fix – When managing SIM contacts, the app might FC if you reenterit after exiting by pressing the Home button
Fix – When adding an extension number to contacts after calling it,the number would show incorrectly
Fix – If set a contact's birthday to February 29 without choosing

the year, it would show as March 1
[Lockscreen, Status bar, Notification shade]
Optimization – If a theme needs to unlock by swiping upward, the

upward arrow wouldn't show
Optimization – Added gradual black change when there's no

lockscreen password
Optimization – Transition animation of Notifications page and

Toggles page
[Home screen]
Optimization – Optimized icon size
Optimizaiton – Icon shadow is turned off by default
Fix – When searching apps in the dock, the app's icon didn't show

completely
Fix – Sometimes, icons couldn't be moved to the right of the dock
[Gallery]
Fix – After user upgraded versions, app would FC
[Weather]
Optimization – Optimized UI for extremely hazardous AQI
[Mail]
Optimization – New version of MIUI Mail
[Calendar]
Fix – The screen wouldn't turn off after being waken up by pop-upreminder
Fix – Sometimes, the homescreen widget showed months incorrectly
[System]
Fix – Open SSL security flaw

[ Lokskrin , Status Bar ]
[+] Incoming calls and messages will only be displayed in the status bar in full-screen action , for example when watching videos .

[Browser ]
[O] Support for use of abbreviations as you type in the website address (Nexus 7 II)

[Security]
[F] Sometimes cleaning is not working

[Music]
[O] Improved interface and fixes some bugs (Nexus 7 II)

[Mail]
[+ ] Support for thumbnail view
[+] Support for viewing unread messages and marking one touch
[O] Ability to upload an attachment not only Wi-Fi network
[O] Search through the server using Exchange account
[O] Improved algorithm for downloading attachments when memory
[O] Improved algorithm to save a draft
[O] Quick reply will be canceled , if you hold the slide to the right to Drafts , Outbox, and Sent
[O] Icons types of investments will be centered. Support for viewing bmp and gif images
[O] Removed two -byte space at the beginning and end of the name of the sender
[O] Improved interface download
[F] Notifications on the status bar is displayed again after removing the slide
[F] Attached images are not displayed
[F] After deleting the account , investments that account will also be deleted
[F] Messages Exchange account is not synchronized if the system settings has been disabled Auto Sync
[F] Sometimes when multiple upgrade fails with data transfer
[F] It was impossible to set up an account manually
[F] Contact information is not displayed correctly when you click on a contact photo

[Messaging]
Optimization – Support recognizing time information in a message and adding it to Calendar (5-21)

[Lockscreen, Status bar, Notification shade]
Optimization – The two arrows of the Data toggle always show when connecting data (Redmi 1S WCDMA/CDMA, Mi3 WCDMA/CDMA) (5-20)Fix – Sometimes, the No SIM Card icon would not disapper (5-21)

[Camera]
Fix- Sometimes camera lost focus when flashlight was turned on (Mi3 WCDMA/CDMA) (5-22)

[Music]
Optimization – Popup menu of online music list (5-20)
Fix – Some bluetooth earphones wouldn't show music information on it's screen (Mi3 WCDMA/CDMA) (5-20)

[Weather]
New – Added two weather types: Freezing rain and hail (5-20)

[Settings]
Fix – Incoming calls from people in the exceptions list of DND did not ring (5-20)

[System]Fix – Sometimes could not register Xiaomi Account using the current phone number (Mi1/1S) (5-22)
Fix – Could not use VPN (Mi3 WCDMA/CDMA) (5-22)

[Calendar]
Fix – Sometimes app would FC in opening (5-20)

[Blocklist]
Fix – DND exceptions list and Blocklist exceptions list caused conflict (5-20)

[Clock/Calculator]
Fix – Sometimes alarm clock delayed in ringing (5-21)

[Mi Cloud]
Fix – After choosing Do not merge in the popup window of merging Mi Cloud data, it did not direct to the next step (5-20)