Cash back and promo code not working

I have the latest version of mobikwik but when entering the promo code eg UP25 it says please upgrade to latest version of Mobikwik to avail the cash back and promo code. Developer must fix the issue at the earliest. Wonder how this app still continuing on Apple Store,does not deserve a place here.

Mdkhalidh about MobiKwik: BHIM UPI & Wallet