I have been very upset that my iPhone 6 has slowed down a great deal. My battery was tested and it showed it to be healthy. Think Apple has done this so that it will force you to buy an iPhone 8 or an iPhone X. I do not buy their excuse the new software does not run on the older phones. My iPhone was running perfectly until they slowed it down through a software update and this was originally done without the customer's knowledge. I also learned for the first time today that when Apple does a screen share on your computer they record your computer. As a customer, I don't like the fact you are forced to have your computer recorded if you need to screen share with a tech agent. I don't think any customer wants their computer information recorded. There is no telling what Apple will do with that information. We saw the problems with what Facebook did with their members' information.

Hello....,
we apologize for this problem and we will try to fix it as soon as possible. please try to install the latest ios update? (I did that and the phone became even slower)

https://www.apple.com/

Apple is trying to make the old iPhones like iphone6 and iphone7 become slow to force you to buy iPhone x and 10. Don't install any software update if you have iPhone 6 or 7.