Aqara has released new firmware for the FP300 when used in Zigbee mode. However, if you are using this with Home Assistant and Zigbee2MQTT, there’s no automatic OTA update available inside of Home Assistant.
I wrote a blog post on how to use the Aqara app to update your FP300 to the latest firmware. It retains all Z2M and HA settings. Just takes a few minutes per device.
To my knowledge Aqara does not release the download URLs for their firmware. In addition, prior methods to root Android and intercept download URLs is now no longer viable due to changes in the Aqara app OS requirements, from what I’ve been told.