Alternativ till Bookis för Slack med kommersiell licens

• Slack
  Alla plattformar Windows Mac Linux Chrome OS Android iPhone Windows Phone iPad Android Tablet Web Self-Hosted Software as a Service (SaaS) PHP jQuery Windows Mobile Slack Microsoft Office Outlook Chrome Google Calendar Sunbird Google Apps Microsoft Exchange Server Apple Calendar
• Kommersiell licens
  Eventuell licens Gratis licens Open Source-licens Kommersiell licens