iScreensaver 5.2 has been released, and provides support for macOS High Sierra 10.13. Please read the 10.13 High Sierra Tech Note
as well as the Release Notes
. macOS 10.14 Mojave is under investigation, and is not yet recommended.
[Solved] Mac OS X users asked to update Quicktime on Sierra
Here is a quote from a user
"I'm running Mac Sierra. When I double-click the screensaver, a window says:
QuickTime plugin is not installed. QuickTime plugin version 7.6.0 is recommended. But Sierra is longer supporting this if I understand correctly. Can you help me?"
Please advise what my response should be.