The all-new iOS 16 drops on September 12. You can update your iPhone manually or automatically from the Software Update section of the Settings app.

Some of these directions apply to all iPhones, but some are only relevant to specific iOS versions. These differences are pointed out below. The most common way to keep apps updated on your iPhone is ...

I'm not seeing reports of iOS 26 installs going sideways, but I still always take these steps before making a major upgrade.