I want to update 14.4 Version.

For the iPhone 7, you can update to iOS 15.7.3. To accomplish that, please see: Update your iPhone, iPad, or iPod touch - Apple Support

And: If your iPhone, iPad, or iPod touch won't update - Apple Support

If the above Apple articles do not help, please post back with relevant information. 

No other update will be available.

For an iPhone 7, you can only update to iOS 15.7.3. Go to settings - general - software update and start there.