Now, though, the $19.99 server bundle will work on multiple versions of OS X.
Although the desktop version of OS X is free (if you've bought a Mac, that is), the server app costs $19.99 and until this year had to be re-purchased for another $19.99 with each new OS release. This change is a break from Apple's past policy. The same version of Server can be used on Mac computers running OS X Yosemite 10.10.5 and OS X El Capitan 10.11,' Apple notes. 'OS X Server 5.0 is now operating system version independent. Further Reading A power user’s guide to OS X Server, Yosemite edition
