In Evo 2.30.3, when I create a new meeting called "test" (with myself as the only attendee), then save/close it, then reopen it, then save/close it again, I get an error that says: "This message cannot be sent because you have not specified any recipients.\n Please enter a valid e-mail address in the To: field. You can search for e-mail addresses by clicking on the To: button next to the entry box." (even though I _am_ listed as an attendee/recipient).

Then the calendar window disappears, and then when I try to close the main Evo window, it says "Are you sure you want to discard the message, titled 'test', you are composing?\nClosing this composer window will discard the message permanently, unless you choose to save the message in your Drafts folder. This will allow you to continue the message at a later date." I.e. the calendar meeting window disappears, but Evo still acts like it's open.

The above functionality used to work okay in 2.28.3. I guess there's potentially 2 bugs here - the prompting about attendees when it shouldn't, and the thinking the window is open when it isn't.

I asked on the mailing list and received some more info from Milan:
> It's a bug, maybe filled already. It may not ask for sending a change
> notice if there is no recipient. The thing with this was that from
> meeting attendees were removed an organizer, and because you were the
> only attendee and the organizer, then the list of recipients got empty.
> What tries to tell you the composer, which is hidden behind the scene.
> It's not doing exactly this on git master, but it still asks for sending
> a change notice when it may not.

IMHO, a meeting with one attendee (e.g. the organiser) should be fine. I frequently block out times in my calendar this way with meetings where I'm  intending on inviting other people when the details of a something are resolved, but don't add them until this is done. It works well, and I don't see any reason why Evo should prevent this.