XCode8 How to use CocoaPod frameworks written in Swift 2.3 (CocoaPods Lagecy Swift)

If you are developing iOS apps with using XCode8 (with Swift 3.x or Swift 2.3) but your CocoaPod project always gets compile error because of your 3rd party targets implemented in Swift 2.3, you need to set SWIFT_VERSION property in build settings to '2.3'.

For dynamic frameworks, this property shown as "Use Legacy Swift Language Version" - Yes, No.

But after every pod update, CocoaPods removes this settings from Pods project and you need to set this settings again, manually.

To acheive this problem, you can use post_install script below in your Podfile :