- iOS 9.1
- OS X El Capitan 10.11.1
- WatchOS 2.0.1
Apart from some new emoji not much has outwardly changed, though there are lots of improvements under the hood to fix bugs and increase performance and reliability. Since this is simply a maintenance update I recommend everyone who has upgraded to the new generation of software to install these updates immediately. If you have yet to upgrade now might be a good time to consider making the jump since the software is maturing quite nicely.
Note that after performing the upgrade you will probably need your Apple ID/iCloud password, so be sure to have that handy.
iOS: iPhone, iPad, iPod Touch: visit Settings > General > Software Update. You may need WiFi and power.
OS X: Go to the Apple Menu > App Store > Updates tab. After it loads there should be an “Update” or “Update All” button.
Apple Watch: on your iPhone go to the Watch app > General > Software Update. Your iPhone will need to be connected to WiFi, your Watch will need to be connected to the charger, and your Watch needs at least 50% charge, even with it plugged in.