Symptom: "Réponse serveur non authentifiée (signature invalide)" on
license activation. Root cause: PHP \DateTimeInterface::ATOM emits the
server's local timezone offset (e.g. +02:00 on a CET host), while the
C# canonicalizer emitted +00:00 after ToUniversalTime(). Same instant,
different string, different bytes, signature mismatch.
Server (ValidateLicense.php):
- All timestamps now built with `new DateTimeZone('UTC')` and formatted
as 'Y-m-d\TH:i:s\Z' — fixed string, no offset variation.
- Reads issued_at / download_entitlement_until from MySQL as UTC; the
display is consistent with what the client sees.
Client (LicenseService.cs):
- FormatDateAtom now produces "yyyy-MM-ddTHH:mm:ssZ" with literal Z and
handles null safely (previous version would have produced "Z" alone
for a null input thanks to string + null concatenation).
Both sides therefore agree on the canonical bytes for any datetime,
including across daylight savings transitions.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
j.foucher
1a3910ef9d