a one-off annual cycle check is impossible within exactly one year

[janwillemstegink]

RFC 9116: The "Expires" field indicates the date and time after which the data contained in the "security.txt" file is considered stale and should not be used (as per Section 5.3).

RFC 9116: It is RECOMMENDED that the value of this field be less than a year into the future to avoid staleness.

Suggestion 1: The data contained in the "security.txt" file MUST expire on the date and time as in the "Expires" field, due to the desirability of an annual audit cycle.

Suggestion 2: For the one-off annual cycle check to work, the "Expires" field date and time is maximally 398 (366+31+1) days into the future, equal to the TLS Certificate Lifespan.

Suggestion 3: Annual audit requires a scheduled date on an office calendar; and customer requests cannot be dealt with if concentrated in one part of the year.