Why is DocsPlus saying my Mac OS isn’t high enough when it is?

You receive this error when trying to install DocsPlus on a Mac, despite its macOS version being high enough.

Resolution

This is caused by the presence of a Server app in your Applications folder.

The solution is to move it temporarily while you install DocsPlus:

1. In Finder, open the Go menu and click Applications.
2. Right-click the Server app and choose Move to Bin.
3. Install DocsPlus.
4. After successful installation, open the Bin. Right-click the Server app and choose Put Back.