According to WABetaInfo, the latest WhatsApp beta update for Android 2.24.18.2 includes details about this PIN feature.After selecting a unique username, users will be prompted to set up a PIN.This PIN must be shared with others to initiate a conversation using the username, allowing users to manage who can message them and block spammers.However, the release date for this feature hasn't been announced yet, as it's still under development.In addition to this feature, WhatsApp is also working on a new option that will allow users to easily block messages from unknown senders.