How can I download iOS 15 on my iPhone 8 Plus?
Hi I’m Reema
[Re-Titled by Moderator]
iPhone 8 Plus, iOS 14
Question marked as
Sorry but an iPhone can only be updated to the most current applicable iOS …
… which for an “8” is iOS 16.7.10.
If you’re really running iOS 14 as your tagline indicates; it’s generally considered most reliable to perform such a “generation skipping” update using a computer and a cable (vice wirelessly).
Update your iPhone, iPad, or iPod touch with the Finder - Apple Support
or
Update your iPhone, iPad, or iPod touch with iTunes - Apple Support