STORE Command

[twitchyliquid64]

  The STORE command alters data associated with a message in the
  mailbox.  Normally, STORE will return the updated value of the
  data with an untagged FETCH response.  A suffix of ".SILENT" in
  the data item name prevents the untagged FETCH, and the server
  SHOULD assume that the client has determined the updated value
  itself or does not care about the updated value.