WhatsApp 限時訊息功能快將推出，而 WhatsApp 亦在官方網站的 FAQ 內講解限時訊息的使用詳情。
用家啟用 WhatsApp 限時訊息功能後，在個人或群組對話中發出的訊息會在七天後消失，設定不會影響先前該對話內收發過的訊息。在一般個人對話，對話雙方都可以選擇開啟或關閉限時訊息功能，而群組通話中就只有管理員有權限開啟或關閉限時訊息功能。
另外，使用限時訊息有幾項要留意。若果使用超過七天後才打開 WhatsApp，訊息將會消失。但若七天後訊息預覽仍有保留的話，有可能在預覽中看到該訊息。
若回覆限時訊息，加上引號的文字在七天後仍可能會留存於對話中。而將限時訊息轉寄至限時訊息功能關閉的對話中，該轉寄訊息不會在對話中消失。至於多媒體內容若果在限時訊息中傳送，多媒體檔案也會消失，但若果多媒體已經下載的話，檔案仍是會儲存在手機內。
If a user doesn’t open WhatsApp in the seven day period, the message will disappear. However, the preview of the message might still be displayed in notifications until WhatsApp is opened.
When you reply to a message, the initial message is quoted. If you reply to a disappearing message, the quoted text might remain in the chat after seven days.
If a disappearing message is forwarded to a chat with disappearing messages off, the message won’t disappear in the forwarded chat.
If a user creates a backup before a message disappears, the disappearing message will be included in the backup. Disappearing messages will be deleted when a user restores from a backup.
Source: WhatsApp FAQ