Why I can’t update my iOS 12.5.7

Hello~ What model iPhone are you trying to update?

~Katana-San~

Why I can’t update my iOs? How to update iOS?

That's not technically possible, sorry.

See why in this compatibility list:

Facebook app

I want to use Facebook

How can i update my iOS to14

Hello~ Take a look at the answer and chart provided by *ProustGiulio* as it answers well.

~Katana-San~