The curving of the blades I don't think is intended to support faster blade speeds at all, but rather scoop air more efficiently. Computer modeling has enabled designers to develop much more advanced blade designs.
And BuffloBagel is right, I got that part wrong. I think what I was trying to say is that a turboprop supports faster aircraft speeds than a traditional engine. But yes, the propeller remains subsonic.
Edit: So apparently the Tu-95 does have supersonic turboprops. But I think it's the only production aircraft with them. Also, it's loud as hell.
https://en.wikipedia.org/wiki/Tupolev_Tu-95
And BuffloBagel is right, I got that part wrong. I think what I was trying to say is that a turboprop supports faster aircraft speeds than a traditional engine. But yes, the propeller remains subsonic.
Unless you're experimenting with madness: https://en.wikipedia.org/wiki/Republic_XF-84H
Edit: So apparently the Tu-95 does have supersonic turboprops. But I think it's the only production aircraft with them. Also, it's loud as hell. https://en.wikipedia.org/wiki/Tupolev_Tu-95