Activity: Read Receipt Event
A read receipt event is sent when a user has read a message, and in the UI shows as an eye icon next to the message.
app.on('readReceipt', async ({ activity }) => {});
'readReceipt' is alias for the event name 'application/vnd.microsoft.readReceipt'.
Read receipts
Bots can also subscribe to read receipts to track when a message has been read by a user. For example, if a read receipt is not received by the bot, the bot could send a follow-up message in personal chat.
Please note that in Teams, the RSC ChatMessageReadReceipt.Read.Chat permissions must be added to the app manifest to receive read receipts.