My understanding is that you will be able to use Gen patches with the standard M4L license, but will only be able to edit them if you have a Gen license as well. Whether this would mean one would have to own a full Max 6 license is unclear, as there is currently no option to own only a Gen license without a Max 6 license.

EDIT: and as a Max/Gen user I can confirm that the capability to edit and use Gen patches exists with M4L in Live 9 (it exists in Live 8 but it's not officially supported).