Right now it is not possible to get floodgate compatibility because loginsecurity does not allow to get special characters like . or + and I think there should be a way to allow to use the character . or + as an option to have floodgate compatibility, because if you disable the special characters in the config, you put at risk the security of your server, so this way, you would only be enabling one special character and not all of them.
I don't know if there is another way to add this compatibility with a single special character right now, but I think it's something they should consider adding.
Right now it is not possible to get floodgate compatibility because loginsecurity does not allow to get special characters like . or + and I think there should be a way to allow to use the character . or + as an option to have floodgate compatibility, because if you disable the special characters in the config, you put at risk the security of your server, so this way, you would only be enabling one special character and not all of them.
I don't know if there is another way to add this compatibility with a single special character right now, but I think it's something they should consider adding.