Even if you successfully install an older version, WhatsApp often displays a "This version is expired" or "Update required" message that prevents you from messaging.
Yes, but only if you already installed it before the cutoff. New installations are nearly impossible without sideloading, and even then, reliability is low.
WhatsApp ceased all support for iOS versions earlier than 12 in 2022, and as of May 5, 2025 , it requires at least iOS 15.1. 32-Bit Obsolescence: