This is with both Skype and Outlook open. Calendar status does not automatically update in Skype for Business for Mac. I am using Skype for Business for Mac 16.7.175 with Outlook 2016 for Mac 15.34 (170515). For previous versions of Skype for Business, only those that have extended support may continue to work with Microsoft 365 or Office 365, although with reduced functionality.
Microsoft 365 and Office 365 work with any version of Skype for Business that is in mainstream support, which includes the latest version of Skype for Business 2016.