Comment by leoedin

I think in this case it implies choice for the user. There’s an implied “if you want to”. You may use this software if you want to in one of two ways:

That’s pretty clear to me (a native speaker from the UK) - i can’t really see how else it could be interpreted. As another poster said, it’s the same “may” as “you may go to the washroom” or “you may enter now” - which implies consent from the speaker.