A new "timestamp" entry for the JSON POST request (/api/v1/store) was added.
The timestamp must be formatted following ISO_OFFSET_DATE_TIME, eg:
YYYY-MM-DDTHH:mm:ss.SSSZ.
The storage request will be denied in case the timestamp is missing, or if
it's more than 5 minutes old (or more than 1 minute into the future).