Apple has announced its next big event where it is expected to show off the iPhone 7, or the iPhone 6SE, or whatever else Apple might decide to call it. While the company will announce the device on September 7, you probably won't be able to buy it until September 23.
There were other rumors that it could launch on the 16th, but that doesn't seem reasonable. The firm typically releases the device on a Friday and the latest iOS update on the previous Wednesday. Apple did say that iOS 10 is coming this fall, and only the 21st fits that schedule.
As far as other hardware that may be announced, what that will be is anyone's guess. Last year's event saw the iPhone 6s/6s Plus, iPad Pro (along with the Mini 4), Apple TV, and new Apple Watch colors. All of those products are a year old now, so a refresh is possible.
And then there are Apple products that are even more stale. The Apple Watch will have been announced two years ago (although it wasn't released until the following spring). The MacBook Pro is another device that's crying for a refresh, and let's not forget about Thunderbolt Displays.
It's not uncommon for the company to have two events in the fall, so if there is something that you're anxiously awaiting and it doesn't show up next Wednesday, check back in October.