4.4. build available here.
Two ways to install
- Flash this file using recovery
- Flash this file using
fastboot
fastboot reboot bootloader
# to 'dirty flash'
fastboot --skip-reboot update iode-4.4-20230817-sunfish-img.zip
# clean flash - will remove user-installed apps & data
fastboot --skip-reboot -w update iiode-4.4-20230817-sunfish-img.zip
Whichever method you use, make a backup before flashing just in case 
Enjoy!