iPhone 6S, 7, and the first generation of SE will not receive iOS 16

Every time there is a new version of iOS, it is inevitable that some iPhone models are left behind for not having enough power to move it. Some would say that it is planned obsolescence, but since mobile operating systems are increasingly multidisciplinary and require compliance with security agencies, it is not uncommon for older models to be left behind. The same is going to happen with iPhone models that will not be able to use iOS 16.
Apple has released a few days ago new details about iOS 16 at its World Developers Conference. In that conference they clarified the phones that will be able to receive the update, and which ones have not passed the cut.
Which iPhone will get iOS 16? iPhone 8 or higher
To download iOS 16, you'll need an iPhone 8, released in September 2017 or later. This means that Apple is ending support for the iPhone 6S, iPhone 7, and the original iPhone SE.
The iPhone 7 and iPhone SE were released in 2016, while the iPhone 6S was released in 2015. This means that these models received almost six and seven years of software support, respectively. That's a lot longer in official support than Android devices have historically had, even though Samsung and Google have made significant strides in that department. Its mid-range and flagship devices now receive up to five years of security updates.

The first-generation iPhone SE has recently been replaced by a 2022 model that keeps the home button from the 2016 edition. If you own a 6S or SE and like that form factor, you don't have to give it up just yet. . In the case of SE 2022, will probably see software updates in the second half of this decade. If you have an upgrade-eligible iPhone, you can expect iOS 16 to arrive this fall.
If you don't have it, from the date of arrival of iOS 16, your mobile may be exposed, and at some point, the apps will no longer be operational, since they will ask to have an updated mobile. It is the inevitable last step in the life cycle of a device designed to be connected, when there comes a time when it can no longer be physically connected due to limitations that were not known for years.
Source: The Verge