We are building a custom meeting booking system into Salesforce and are hoping to send the event/calendar invitations through Marketo. This includes any updates (like changing the date/time) or cancelling the meeting altogether.
If the ICS invitation system built into Marketo does not allow events to be updated (using the UID value), I am wondering if it is possible to build the ICS file into a Marketo email another way (like building a custom email outside of Marketo that includes the ICS info, and sending that email through Marketo like with the MSI gmail plugin).
More info on updating ICS files here:
I (naturally!) recommend using Agical.io in place of Marketo's calendar tokens. An Agical URL can include the optional parameter uid, which hard-codes the UID so you can update the same appointment later.