Why can't my iPhone X follow updates?

The iPhone X got a number of major version updates.

When Apple introduced it in November 2017, it ran iOS 11.0.1. It was eligible for updates to iOS 12, 13, 14, 15, and 16. That's five major versions.

iOS 16 is the end of the line. The iPhone X cannot run iOS 17 or later.

iPhone X is not compatible with iOS 17. It can only update up to iOS 16.7.9

Source: Apple security releases - Apple Support (CA)and iPhone models compatible with iOS 16 - Apple Support (CA) and iPhone models compatible with iOS 17 - Apple Support (CA)

ivanchouu wrote:

because the iphone x cannot follow updates if it is not very old

It isn’t clear what you are asking, but the iPhone X is 7 years old, and its hardware cannot support features in iOS version 17 and higher.