Apple's new iOS 14 is compatible with many older iPhones, including the original iPhone SE, the iPhone 6s and iPhone 6s Plus.
This means the new update can be applied to iPhones older than 5 years.
Apple's list of compatible devices :
iPhone 11
iPhone 11 Pro
iPhone 11 Pro Max
iPhone XS
iPhone XS Max
iPhone XR
iPhone X
iPhone 8 and iPhone 8 Plus
iPhone 7 and 7 Plus
iPhone SE
iPhone 6s and 6s Plus
iPod touch (seventh generation)
The new iPadOS is also compatible with a variety of older devices.
All iPad Pro
iPad (seventh generation)
iPad (sixth generation)
iPad (fifth generation)
iPad mini 5
iPad mini 4
iPad Air (third generation)
iPad Air 2
iOS and iPadOS 14 will be limited to registered developers at launch, but Apple plans to make them available later this summer with a public beta.
iOS and iPadOS 14 will be available to the public in the fall.