Guys,
Somfy has switched off the old good v1 API, so we have to migrate the binding to v2.
I have created a PR containing the required changes. (https://github.com/openhab/openhab2-addons/pull/6500)
Hopefully it will be soon merged in 2.5 so we can catch the final OH 2.5 release.
Until this happens, please see post #324 and #329
Good luck,
Ondrej