As a side effect of the version fragmentation that Android suffers from, even the latest apps tend to support Android versions a few years old. For example, most of Google’s apps nowadays have a minimum requirement of Android 4.1 or 4.2. If you’re still stuck on 2.3 Gingerbread, at least you’ll get to keep using WhatsApp.
Last year, WhatsApp said it was ending support for a variety of older mobile operating systems, like iOS 6 and Android 2.2 (and below).
WhatsApp will continue to support Android 2.3 until 2020 was written by the awesome team at Android Police.