One-Way
All 3rd party calendar communication is one-way.
RBPro can insert/remove data from the 3rd party calendars but they have no knowledge of RBPro .
Changes made in 3rd party calendars have no effect in RBPro.


Technical stuff
RBPro adds/removes bookings by directly accessing the calendar’s database tables. No 3rd party calendar has any knowledge of RBPro and so any changes made in the 3rd party calendar will have NO effect on RBPro .

JEvents and JCalPro used to be pretty much the same as far as functionality.
JCalPro looked much better but was not free.
JEvents was(is) free.
EventList is not a calendar at all but people using it wanted integration with RBPro.
Google Calendar is my favourite. Easy to setup and use. A nice feature of Google is its ability to sync with Outlook’s calendar.

With the latest versions;
RBPro supports either JCalPro or JCalPro2 (RBPro will not be supporting JCalPro3)
JEvents did a total re-write moving to iCal design and ABPro does NOT support the new version. The way RBPro talks to 3rd party calendars is by inserting and removing data from tables. The iCal data model is very complex and the JEvents authors have told me that accessing the data tables directly would be very difficult. I have taken them at their word and dropped support for JEvents.
JEvents 1.5 is not supported.