Obviously you have to flash lineage recovery in order to do the firmware update. So TWRP is gone, anyway. I asked about wiping because it is not mentioned in the fw update and LOS upgrade instructions.The reason I said wipe before is because once you update the firmware files to the new ones TWRP won't boot up. At least for me it does not. Unfortunately you will be stuck with lineage recovery which works fine but when I choose factory reset in lineage recovery it forces you to format data (which includes the internal storage). I don't know about you but for me having to format DATA just to make a clean install is painful.