Message

IssueTime MUST have a granularity of seconds

Context
/ubl:AwardedNotification/cbc:IssueTime
Test
matches(normalize-space(.),'^(([01][0-9]|2[0-3]):[0-5][0-9]:[0-5][0-9]|(24:00:00))(Z|(\+|-)((0[0-9]|1[0-3]):[0-5][0-9]|14:00))?$')
Usage
/ t017:AwardingNotification / cbc:IssueTime