The uneven treatment of Windows and Mac versions

TeamViewer 13 runs on 8-years old Windows 7, but will not run on 4-years old OS X 10.9 Mavericks.

This makes TeamViewer 13 completely useless to me for use on my Mac. 

And TeamViewer 13 Quick Support does not allow connections from the Mac TeamViewer 12 client app.

This is how you lose customers.