Integration with Lotus Notes

The Plain Java Client Libraries can be used to create automation to add scheduled absences in EWM. There might even be a REST API. Not sure. I know that some customers have created tooling for this. There is no marked for this kind of automation. There are too many tools out there.

Our users normally use Lotus Notes, and this includes a diary function
which they use to schedule meetings, holidays, etc. They'd like to
mirror the calendar information to the 'Scheduled Absences'
information in RTC, but the only mechanism that's readily available
for sending this information from Notes is an 'interested party'
email notification.
Is it possible to update the 'Scheduled Absences' information for a
user without using the GUI? If so, does RTC contain any function
that's capable of handling an incoming email and updating a user's
scheduled absences, or would we need to write something to do this?
Or are there any plans for a Notes-connector?