API:ClearHasMsg

ClearHasMsg
This action will remove the HasMsg flag, which causes the "You have new messages" banner to appear and returns true in HasMsg query. It can be used by application that retrieve the talk page using api, which unlike opening your talk page in browser, doesn't automatically remove this flag.

When you trigger this action, the banner You have new messages will not appear until you receive any more messages from other users.