UTC-GMT-ZULU Time, displays the local time, the date as well as the Zulu time, Military time and Astronomical time along with the current UTC time in a 8601 ISO Standard. UTC time (Coordinated Universal Time) was made the world standard for time in 1986, replacing Greenwich Mean Time (GMT).
Synchronizing your smartphone clock;
If your smartphone is a member of a domain, your smartphone clock is probably synchronized automatically by a network time server. If your smartphone is not a member of a domain, you can synchronize your smartphone clock with an Internet time server.
If time synchronization fails;
Since the Date & Time service is a cloud computing solution, it may be affected by the distance from the server, the data rate and data traffic of the network connection and the local network policy (firewall).
Sometimes, the connection with the smartphone will be interrupted, which may seem like the connection with the smartphone is disconnected.
The date set on your smartphone is inaccurate. Internet time servers will not synchronize your clock if the date is incorrect. Ensure that the date and time is set correctly in Date & Time properties in settings tab.
You are not connected to the Internet. Establish an Internet connection before you attempt to synchronize your clock.
Your personal or network firewall prevents clock synchronization. Most corporate and organizational firewalls will block time synchronization, as do some personal firewalls.
New user interface.
When you tap the 12/24 button, the local time change to 12 or 24 hr format.
When you tap the Moon/Sun button, the app change the brightness.
When you tap the home button, the app stays open in the background.
When you tap the back button, the app closes.