To easily finding messages a date filter is enabled in your inbox, as well as a selection filter for All messages, Unread messages or Drafts.
To find relevant messages in the inbox you can search for them in your inbox by using a date selection. When searching from a date and to another date, the service will filter on messages that has any action in this period, showing any new messages or reply to an ongoing conversation within the period selected.
If you are looking for a message related to a board meeting that was conducted in September, you can easily select the period of September to find all relevant messages or replies.