Today, September 12 at 10 a.m. PDT, you can watch the keynote presentation where it is widely believed the new iPhone X will be introduced. Along with the new iPhone, there may be some new information about when the new iOS will be available. There may also be some news about any new or updated hardware for devices like the iPad.
You can watch the presentation livet here.
While waiting, you can learn more about iOS 11 here.