IKEA devices not upgrading firmware

Hmm, do you have old config? I thought OTA for IKEA had been specifically disabled by default in ZHA?

But be glad, you do not want to just upgrade all anyway to later IKEA firmware because those newer firmware are infamously known to have bugs, see warnings that ZHA integration have about updating Zigbee device firmware if devices are working fine (do not try to fix what is not broken):

Zigbee2MQTT documentation has a similar warning:

If you want ot know more MattWestb maintained a matrix and discussion thread about IKEA firmware here (that discussion thread has however not been updated in 6-months so things might have changed since):

Anyway, the most common reason for Zigbee OTA firmware update failure is due to eother EMF interference or having to few Zigbee Router (Zigbee repeaters/extenders) devices and long distances, read + follow this: