In this page you will find all iPhone generations with the most popular iPhone feature added with each new iPhone. I will emphasize on the features that Apple introduced to push the sale and make that generation iphone the product of that year.
You will see that with each new iPhone generation apple would introduce something new that was either new to the world, new to smart phones, or new technology that was never seen before on another hand held devices. The idea is of course to market the new iPhone generation and encourage people with previous iPhone to upgrade to the new iPhone.
Of course with every new iPhone, the screen size and iPhone screen resolution, the hardware, the processor, the camera, and the internals are always in a continuous improvement. You will see speed boost of at least 2 time or or more from one iPhone the next generation iPhone. This will apply in all apple iPhones.
But I will be focusing on those unique features that are new to the industry. For those iPhones that really didn't offer something unique, I will just call them having new internals which would imply that this iPhone generation didn't offer something really unique compared to the previous generation.
Also as you move from one iPhone generation to another, the same features of the previous generations are usually carried over to the new iPhone plus some new added unique features.
When the feature is fist introduce to that specific iPhone generation, you will see it for that iPhone, but I will not repeat it as you would assume that apple wouldn't usually remove a feature but would kept adding new features to the new iPhone.
For example, if Apple introduced water resistance capability to iPhone 7, then you would assume that the next generation iPhone 8 will also have that feature and so on.
iPhone Xr: October 26, 2018
6.1" screen size
Lower screen resolution of 828 x 1792 points
326 (PPI) Pixel Per Inch
No force touch (force touch removed from iPhone Xr only)
Apple introduced force touch (on the screen so when you apply pressure to the screen you can get menus and more options, similar to a right click on a computer mouse.)