Help to change the iOS version to new versions

You cannot update to iOS 15.2 - if you can update to iOS 15, then you must upgrade to the latest version, as here iOS 15.7.3. When you install a new version, the old one is automatically "overwritten" - so you don't have to worry about deleting an old version before installing a new one.

You don't write which iPhone you have now, but here you can see your options:

• iPhone 5S/6 can be updated to: iOS 12.5.7
• iPhone 6S/7/SE 1.Gen can be updated to iOS 15.7.3
• iPhone 8 or newer can be updated to: iOS 16.3.1

You can check your current version here:

Settings → General → About

You can download and install software updates here:

Settings → General → Software Update

Remember to connect to Wi-Fi and a charger. Your iPhone must have more than 50% power to update without a charger connected.

You can find more useful information here:

Update your iPhone or iPad - Apple Support

If you want to update your iPhone via a PC or Mac, see here:

• Mac: Update your iPhone, iPad, or iPod touch with the Finder - Apple Support
• PC (iTunes): Update your iPhone, iPad, or iPod touch with iTunes - Apple Support

You cannot pick and choose an iOS version. What you get is Settings > General > Software update > [All options are available here]

You need to correctly Identify your iPhone model - Apple Support

These are the iOS options based on iPhone Model -->

• iOS 16.3.1 —>
  • Chipset A11 - 8 / 8 Plus / X
  • Chipset A12 - XR / XS / XS Max
  • Chipset A13 - SE (2020) / 11 / 11 Pro /11 Pro Max
  • Chipset A14 - 12 Mini / 12 / 12 Pro / 12 Pro Max
  • Chipset A15 - SE (2022) / 13 Mini / 13 / 13 Pro / 13 Pro Max
  • Chipset A16 - 14 / 14 Plus / 14 Pro / 14 Pro Max
• iOS 15.7.3 —>
  • Chipset A9 - 6S / 6S Plus /SE (1st Gen)
  • Chipset A10 - 7 / 7 Plus
• iOS 12.5.7 —>
  • Chipset A7 - iPhone 5S
  • Chipset A8 - iPhone 6/6 Plus
• iOS 10.3.4 —>
  • Chipset A6 - iPhone 5
• iOS 10.3.3 —>
  • Chipset A6 - iPhone 5C
• iOS 9.3.6 —> iPhone 4S - Chipset A5
• iOS 7.1.2 —> iPhone 4 - Chipset A4

Know how to...

• Update Over-the-Air (OTA) —> Update your iPhone or iPad - Apple Support (IN)
• Update using iTunes/Finder —> Update your iPhone, iPad, or iPod touch - Apple Support (IN)

Owolabi2 wrote:

I have also trying all this

the iOS stills not update

Correct, as your device is not compatible with higher versions of iOS.