DOC: expire date format?

[Sispheor]

I don't see anything about the required date format.

"expire": expiration of notification, after this date it disappears

[guglielmino]

You are right I have to update the doc.
Anyway date format is "yyyy-mm-dd"

[Sispheor]

I can see you've let the default format. Following the doc the default format is 'iso-8601' (eg '2013-01-29').