When does support end for iPhone 10?

The iPhone X has already reached the end of the line as far as major iOS updates.

It can run the latest version of iOS 16, but cannot run iOS 17, 18, or 26.

Apple has not said, but a reasonable guess would be sometime later this year.

At this time, the iPhone X is classified as Vintage, meaning that it is still supported, but some parts may not be available if repairs are needed.