My iphone 6 after update too slow

If this is available in your area, make an appointment at your nearest, “local” Apple Store or authorised Apple repair center to get your iPhone 6 battery replaced under Apple’s reduced price iPhone battery replacement program for iPhone 6 and newer iPhone models.

Your iPhone 6 is slow and getting slower under iOS 11 as Apple injected CPU slowdown code at the introduction of iOS 11 that slows down older iPhone 6/6S/6S Plus when the software detects a less than optimal performing or degrading performing battery.

You get the battery replaced in your iPhone 6 and most of your iPhone 6 previously normal performance will return.

Good Luck to You!

I have a 6+ and it was replaced with a new one only 6months ago, this battery should not give the old battery problem that is mentioned here yet it is rediculously slow and lagging. Battery is poor at best but I would rather have a powerbank handy and still have performance as a often i have to wait at important moments for it too catch up. Give us a choice to switch off the code please!

Do you really know how "fresh" was this 6+ replacement phone?

That replacement iPhone could be old new stock.

Was this a warranty replacement iPhone 6+ from Apple or from carrier?

That replacement phone could be older than you think.

And the battery inside of that iPhone, from, possibly, sitting around for a long time not getting charge could, possibly, could already be degraded and is still being affect by the iOS 11 CPU/battery slowdown code.

Call your your "local" Apple Store and make an appointment to get the battery in your iPhone 6+ battery replaced for the $29 charge.

Your replacement iPhone 6+ may need a new, replacement battery.

A new replacement battery WILL return your iPhone 6 to its former, normal operation and performance.

Good Luck to You!