You can upgrade the firmware using a Z-Wave usb stick as a secondary controller and Silicon Labs free "Simplicity Studio".
UZB-7
https://www.mouser.com/ProductDetail/Silicon-Labs/SLUSB001A?qs=u16ybLDytRbJsMfgk3EnSA%3D%3D
Z-Stick+
Zooz Stick
Note: A secondary controller is also useful for removing ghosts and pairing older Z-Wave plus devices with "no security" instead of being forced into "S0" security. UZB-7 is nice because it's cheap, the Z-Stick is nice because it has an internal battery and can be moved around to help with inclusion/exclusions, Zooz is a good price too but I think it's sold out at the moment. Their earlier model is great too.