A number of Spotify users began to notice something strange over the last day or so: the in-app lyrics, which typically pop up under the currently playing song, were suddenly locked away under a paywall. Instead, they saw only a notification bubble saying, “Enjoy lyrics on Spotify Premium,” with a link to sign up. Many Spotify listeners were not enthused.

Spotify tells us that the feature is only a test. “At Spotify, we routinely conduct a number of tests, some of those tests end up paving the way for our broader user experience and others serve only as an important learning,” says CJ Stanley, Spotify’s co-head of global communications. “We don’t have any further news to share at this time.” Stanley later followed up to add that “In keeping with our standard practices, we’re currently testing this with a limited number of users in a pair of markets,” without specifying which markets, how many users, or how long the test might last.

While it’s possible that Spotify will bring lyrics back in front of the Premium paywall, it’s certainly true that the company is on the hunt for anything it can do to get users to pay up. After pouring billions into podcasts and audiobooks to little effect, it seems to have largely given up on the idea that exclusive content is the path to riches. Instead, the company appears to be looking to build other kinds of features users might pay for. That’s especially important as the price of Premium, like so many other streaming services, continues to rise.

The most successful Premium-only feature so far is probably DJ, the AI tool that builds you a personalized radio station. It works surprisingly well, even the AI voice that commentates on the tracks like any good morning radio host, and offers a music listening experience that is genuinely different from what you get on Spotify’s free tier. (HiFi, the company’s lossless streaming option, could be another compelling reason to upgrade, but after more than two years, we’re pretty much done waiting for that.)

Spotify is also continuing to try to embrace creators, bring more video onto the platform, and become the “TikTok for audio” that CEO Daniel Ek has been talking about for so long. Going forward, don’t be surprised to see more of Spotify’s best ideas come only to those willing to pay.

Update Sept. 5th, 6:25PM ET: Added further comment from Spotify.