Error load firmware HW-18.0.0_EAP2.SF300-180 using SFLoader

Hello. I tried to follow the steps of kb 125209 (Sophos XG Firewall: How to load firmware using SFLoader) to install a new firmware on a Sophos xg firewall device, but after step 8 the fwloader displays the following error:

error this firmware needs latest loader. please get the latest fw loader from the repository

Any suggestions?