Sorry for my late reply, yesterday was a national holiday in my country and I was offline.

> I can post that blog post a few days before the migration?
> Or just publish it now?

I'd say publish it now, some people like to be warned way beforehand, especially if they must change their custom scripts to use Bohdi's RSS feeds.

I'd like to complete the migration after Beta is out the door and we
are out of freeze. Either May 11th or May 13th would be fine with me.
We would migrate the last lists, then we need to change things to
proxy everything to mailman01 and take collab03 out of the mix
entirely. If all looks well after a week or so, we can retire collab03.

That sounds perfect, May 11th seems a bit better since May 13th is a Friday, and we all know about deploying on Fridays ;-)

Aurélien