Apple iOS 10 has been available in a beta stage for a while, but that does not mean Apple has dropped iOS 9 development completely. While iOS 9.3.3 solved various minor issues and added a vulnerability that allowed for Apple devices loaded with it to be jailbroken, its successor takes care of this problem.
Apple released iOS 9.3.4 on August 4 and, unfortunately, the document that describes its content only mentions that "a memory corruption issue was addressed through improved memory handling." However, ZDNet's Adrian Kingsley-Hughes thinks "This update is clearly a response to the jailbreak released for iOS 9.3.3 by Team Pangu."
iOS 9.3.4 arrives less than two weeks after a security vulnerability has been discovered by none other the well-known Pangu Jailbreak team. The list of affected devices includes all devices that run iOS 9, basically iPhone 4S and later, iPad 2 and later, all iPad Minis and iPad Pros, as well as the fifth and sixth generation iPod Touch.