So apparently my suggestion was wrong and the update request is sent, it is just not received properly. You said you also tried pressing the ikea button meanwhile to prevent it from going to sleep mode, so I’m kinda clueless here too. Maybe it helps to re-pair the switches? or just waiting for the update to be loaded by the switches themselves, which can take some days. zigbee2mqtt seems at least otherwise correctly configured to serve an ota update.