Previously I have used Ubuntu 12.04 LTS with MATE from your PPA.
indicator-datetime and shown calendar events in Clocks applet.
Similar example is shown in this AskUbuntu Q&A about ordinary Ubuntu:
Currently I have configured Evolution to access my CalDAV. I can execute
/usr/lib/x86_64-linux-gnu/indicator-datetime/indicator-datetime-service, but I have no integration with MATE clock-applet.
Is it possible to get the same functionality on Ubuntu MATE 16.04 LTS?