What constituted the final actual communication signal received from Opportunity before silence?

A data packet indicating it had entered hibernation due to critically low power

While the public heard a poignant sentence, the rover's final *real* message was purely technical telemetry. Because the severe dust storm had depleted its power reserves and the Martian night was approaching—a time when power drain is high and solar collection ceases—the rover transmitted a final data packet. This packet essentially signaled that its internal systems were initiating a precautionary hibernation sequence due to critically low power reserves, marking the last verifiable data exchange before the team could no longer elicit a response.