I have two applications in one device. For iOS 7 both applications are sending different device tokens but for iOS 6 both apps are sending same device token.
As per my understanding device token has to be same for all the application in one device. Is there something different in iOS7 than iOS 6?
This one was also helpful.Please see point 1 in this article: https://support.urbanairship.com/customer/portal/articles/1321513-how-ios-7-handles-push-differently
"Prior to iOS 7, the device token was the same across all app installations on a given device. Different apps on your phone, whether Tap Tap Revenge or USA Today, would utilize the same address, i.e., device token, to route the push notification to you. The security credentials that you pair with a message would ensure it made it to the right app. On iOS 7, Apple has gone one step further and made sure that device tokens are now different in every single app install. This helps further protect users’ privacy by removing another phone-level identifier."
Though this is very late answer, I want to share my test done for i0S 9.2.1. The device token is unique for each app in a device. A new device token will be generated each time we install an app. As far as I know, apple has changed its policy for device token after they released iOS7.
UPDATE:
I guess I read this one a bit too quickly. Please note my revisions. If the answer meets your use-case please feel free to accept it.
Based on your description I would suggest that there have been underlying changes to the token generation between iOS6 and iOS7. To examine this behavior more closely I recommend that you take a look at the Local and Push Notifications Programming Guide. Within the Guide in the section for "Scheduling, Registering, and Handling Notifications," one will find this statement from Apple.
Reference:
Apple uses device tokens when users agree to receive remote notifications from the Apple Push Service.
Typically the device token is accessed in the following method:
There are also significant changes to the UIDevice Identifier (Apple has restricted usage). I would suggest the following reads: