iOS 10 has been in Beta ever since Apple announced the iOS update at WWDC. Starting with a Developer Preview, a Public Beta was made available for those consumers who could not wait to try out the latest iOS release. Apple has used the Beta program to not only eradicate a lot of bugs from iOS 10 but also allow the developers to utilize everything that is new and integrate it with their applications. No wonder that even before the public beta is out, the developers are ready with the app updates that take full advantage of everything that is new with iOS 10.
However, at the event where Apple announced the iPhone 7, they also announced that iOS 10 will be released to public on 13th of September. If you are to go by how things generally are, get ready for a huge section of Apple device users to be already on the iOS 10 public release within a few days. Other than the iOS 10 update, there will also be the update to watchOS 3 tonight itself, while for the MacBook users, macOS Sierra will only be dropping on September 20th.
The time you would want to note, if you are in India is 10:30 PM when you must set your phone to check for the update. Make sure that you are well connected to WiFi and have your phone charged and backed up well before going ahead with the update. As it is the norm, when the update does roll out, there is a possibility that due to high demand, the servers act up, but make sure you keep at it unless you are comfortable connecting your iPhone or iPod to the machine and update via iTunes. Remember, if you have jailbroken your iPhone, updating to iOS 10 will take the jailbreak away from the device.