Has apple stopped updates for iphone 6

Apple stopped updating iPhone 6 (except for important security issues) at iOS 12.5.4. Tomorrow, iOS 15 will be released.

Unless there is some vulnerability which may effect devices on iOS 12.5.4, there may not be any updates forthcoming.

iPhone 6 is going on 8 years since release. It it is too old, too underpowered and lacks the hardware required to run the newer iOS versions.

Yes, long time ago. There will be no future updates, it cannot be updated past iOS 12.