it says, using old IOS version 18.6.2
You need to update the new IOS
But there is no way I see to do that. I am using an iPhone 15 pro
Hello,
Check in Settings → General → Software Update. Since you have 18.6.2 I think you should see two options there, 18.7.1 and below that there should be the option to update to iOS 26, as shown here:
This was taken from iPhone 13 Pro Max, so you should have this as well.
Regards