According to the system requirements posted on the developer's website, the application requires the following to work properly:
Outlook 2007, Outlook 2010, Outlook 2013, Outlook 2016 or Office 365.
Windows Vista, Windows 7, Windows 8 or Windows 10
(including all Windows Server equivalent versions).
Microsoft .NET Framework 4.5 (detected during installation).
As you can see, OutlookTools should work with Outlook 2016.