Let's say Adam invites Claudette to three meetings, which in Meeting Maker she Accepts, Declines, and Decides Later.
Adam's calendar looks like this in Meeting Maker:
And after migration Adam's calendar looks like this in Zimbra:
Claudette's looks like this in Meeting Maker:
And after migration Claudette's calendar looks like this in Zimbra:
Note that the model for display of calendar state information is completely opposite between the two products. In Meeting Maker, the proposer / owner of a meeting is the one who sees an instant display of guest response status. In Zimbra, it is the guest who has the "one glance" view of her response status. In going from Meeting Maker to Zimbra this radically simplifies things for the guest (especially compared with the clunky "proposals box" in Meeting Maker). However, it does make it harder for those used to the symbols Meeting Maker uses to manage meetings to see them at a glance. This information does display very handily in the proposer's mail Inbox as guests make decisions.
Note that we are opting to map "Decide Later" as "New" in Zimbra rather than "Tentative" to highlight the need to make a decision on the meeting.