WhatsApp now allows you to mute a chat forever with the new ‘Always’ option in chat settings. WhatsApp had been testing this feature in the beta version and now it is widely rolling out to the stable version.

source https://gadgets.ndtv.com/apps/news/whatsapp-mute-always-new-feature-silence-chat-alerts-forever-option-android-ios-2314580#rss-gadgets-all