iCloud invites marked as spam, now what?

Invites from iCloud calendars are sent from "My Name <donotreply@icloud.com>." They also contain images that are need to be loaded from iCloud, and the links go to an iCloud Web page. All this causes them to be marked as spam, especially with larger companies I work with who block iCloud. So now what? With BusyCal, I used to have local calendars and then I could see the invites and accepts in Mail.app. Now Apple has dropped support for Sync services, and BusyCal no longer supports syncing local calendars with my iDevices, so are we all just out of luck? What do I use for a calendar? Do I need to run my own CalDav server, or is there any way left to prevent invites from coming from some address other than my own (e.g. intercepting them in Mail instead of connecting to the iCloud server to send them)? Good Lord, Apple, I just want a calendar I can sync. iCloud has taken me back to the 80's, and removed everything about my workflow that mattered unless I and everyone I work with accepts the iCloud infrastructure.

Thanks for any advice.