Warrant canaries need restated and re-signed regularly, daily in this case. That is what makes them canaries as opposed to something like a transparency report.
The government probably can NOT compel you to re-sign and update an expired canary, at least according to the lawyers at the EFF.
Exactly, they (government) can ask you to continue to update, you decline, they sue to force the issue. Highly unlikely the courts rule so quickly that at least one day goes by without an update. This is the signal something has happened.
The government probably can NOT compel you to re-sign and update an expired canary, at least according to the lawyers at the EFF.