Last Year Apple released iOS 8 and it was the biggest release of iOS and now is working to launch iOS 8.1/8.2 and 8.3.
What You Should expect from Apple for iOS 9
Apple is focusing to improve stability and increase performance for iOS 9 and a huge focus on security and fixing bugs. Experts thinks that iOS 9 will be more smoothly and more faster.
If a iOS 7 users needed to be upgrade to iOS 8 it needed him to have at least around 5 to 6 GB free space to download and to instal it because the operating system was very big.
While Iphone 4 does not support iOS 8 it is supossed that iOS 9 will not support Iphone 4/ 4S/ and older Apple Model’s.