Current license keys require an expiry date. A key without one is rejected; keys issued earlier work until the date stored in them.
Activation through the license server makes it possible to count installations and revoke keys. The earlier local check did not provide that control.
The panel renews its lease every 12 hours over HTTPS. The last lease remains valid for 14 days from issue, and after the license expires there is a 14-day grace period. The exact flow is described in the activation guide.
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