I want to know about tha iOS 15

Doeramon wrote:

Why iOS 15 is require for insta

Because Meta, who owns Instagram is no longer supporting their app on older iPhones which cannot run at least iOS 15. If you want Instagram on an iPhone, then you need to own an iPhone which can at least support iOS 15 or higher.

Doeramon wrote:

Why iOS 15 is require for insta

Ask Meta. Their app, their service, their decisions.

For many app developers, continuing support for old devices adds expenses for support and testing, reduces what newer features can be adopted or makes that feature adoption more difficult and complex, and in aggregate that can either be less profitable or can be a cost.

In the case of iPhone 6 and earlier models in aggregate, that usage comprises roughly 1.2% of all iPhone devices in use, and that percentage of older iPhone models is dropping.