iphone6s plus running very slow

About iOS performance on your iPhone, iPad, or iPod touch ...

Make sure you have enough storage You can check your device's storage in Settings > General > [Device] Storage. For best performance, try to maintain at least 1GB of free space. If your available storage is consistently less than 1GB, your device might slow down as iOS repeatedly makes room for more content.

Here is an article I found online showing some tips to help.

https://www.ikream.com/iphone-6s-plus-running-slow-keeps-lagging-crashing-randomly-26396

If these tips don’t work, then I advise you to send your phone in to Apple.

iPhone Repair - Apple Official Support

Are you sure that it is not a WiFi Network issue? Does this happen only on a WiFi Network or also on Cellular data? Do the apps appear to run slow only one particular WiFi Network or all WiFi Networks that you have tried?

Can you Try and Force ReStart your iPhone 6s Plus by Pushing and Holding Down The Right Side Button AND the Home Button for 40 seconds until you see the Apple Logo. See if that resolves the WiFi connection issue.

Axel F.

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