[ratww]

Making a program is not illegal, as long as it's not circumventing anything. If it were, SEND A DMCA. FOLLOW THE LAW.

The API was public, authenticated, documented and intended for third party developers. Even if it was reverse engineered there is still legal grounds for that, as seen by the YouTube-dl situation.

If there was any law-breaking, it would be the people downloading scores and MuseGroup for distributing them.

Repeating what I said below:

Even if musescore-downloader was doing illegal things (and I would argue it wasn't, since there was no circumvention of anything), the law should be followed by both sides, no excuses. That means sending a DMCA instead of a threat.

[zxzax]

This may have been an accident where the legal notice was sent out before taking the API offline. If that's the case I agree they messed up. The DMCA may not apply here.