Unable to download Google Pay on iPhone 7 with iOS 15.8.4

I am using I phone 7 and running version is ois 15.8.4 . I try to download gpay for my payment method but it’s showing need to update into ois 16 when I check for update it’s not showing for update . I am unable to download gpay how can I fix that

[Re-Titled by Moderator]

Original Title: Sharing payment failiure