title: Get last message date visible on a Slack channel
body: <p>Whenever a team exceeds 10000 messages then older messages are not visible in free trial teams.How can I get the last message's date, which is visible on a channel?</p>
  
  <p>For example, Today is February 15,2016. If I have access to a public channel 'ChannelDemo' and my team has exceeded 10000 messages.When i go to channel 'ChannelDemo' and it shows messages from February 14,2016.</p>
  
  <p>How can I get this date Feb14,2016(the date from which messages are visible on my channel - 'ChannelDemo') programmatically or through any method/web api call?</p>
  
  <p>Please suggest.</p>