A specific feature introduced for Android 6.0 and above is . This allows you to quickly select a specific WhatsApp chat directly from the sharing menu of other apps (like your Gallery or Browser), skipping the step of opening WhatsApp first to find the contact.
However, the clock is ticking. WhatsApp has officially announced that starting , the minimum requirement will shift to Android 6.0 and newer, meaning this is currently the oldest supported version. download whatsapp for android 6.0.1