Captain's log wrote:
AFTER ACARS was registered offline
I've heard this several times recently and don't believe it is accurate.
Last ACARS was 17:07, Next ACARS was due 17:37. The 17:37 transmission was never received, leading to the deduction that ACARS was disabled sometime between 17:07 and 17:37. That's the most that can be said on that account.
Last VHF to ATC was 17:19, at that exact time we don't know if ACARS was disabled (offline) or not.
Another system, ADS-B, apparently up and functioning at 17:20 and transmitted lat/lon, speed, track and FL.
What we don't know is what was happening during and after 17:19 (last ATC comms).