ISO timestamp

In both cases, “ttl” and “crt”, the timestamp complies with [ISO 8601]. One supported basic pattern is illustrated below:

YYYY-MM-DDThh:mm:ss+hh:mm

This string pattern represents year, month, day, hours, minutes, seconds, and the UTC time zone offset in hours and minutes as illustrated in the example:

2018-12-31T23:59:59+01:00