Is the Spotify search API no longer available without authentication?

For years I've been using Spotify's search API for various projects. It has always been available to use without authentication.

Example: https://api.spotify.com/v1/search?q=kanye%20west&type=track

Now starting just today it is responding with the following

{
  "error": {
    "status": 401,
    "message": "No token provided"
  }
}

I can't find anything stating that they've changed their search API, but the docs now say authentication is required.

It has previously stated that requests without an auth token would be rate limited. Now it says a token is required. Does anyone know if they've updated their API, or if this is a permanent thing? I find it hard to believe they would make such a drastic change to their API without notice.