Two weeks ago, on its fourth quarter earnings call, analysts grilled Fitbit about its product release cycle and wondered whether Fitbit would be putting out a new fitness tracker this spring, just like it did last year. Turns out Fitbit did have something up its sleeve — but it’s less of a “new” product and more an update to an old one.

Fitbit announced the Alta HR today, an update to last year’s Alta that adds heart rate sensors to the bracelet-like activity tracker. A brief refresher on the Alta: it’s one of Fitbit’s more stylish trackers, and has a tap-sensitive, OLED display and five-day battery life. It tracks steps and sleep and shows notifications from the smartphone, but Fitbit says the number one request it got from customers was an Alta with continuous heart rate tracking. And so, here it is.

Fitbit had to develop a new chip in order to fit its heart rate technology into the tiny Alta wristband

This makes the Alta HR the fourth Fitbit product line to include heart rate sensors; the Charge, Blaze, and Surge also have them. But Fitbit has been developing the Alta HR for nearly a year now, according to the company’s R&D director Shelten Yuen, working with Texas Instruments to try to shrink its heart rate monitor to a size that would fit in the tiny wristband, which is 25 percent smaller than the Charge 2. Yeun said the new Alta will also last seven days per battery charge.

Fitbit is also trying to lure in (and retain) more customers by offering more detailed sleep tracking data, or, what the company is labeling Sleep Stages and Sleep Insights. Fitbit wristbands have automatically tracked sleep for a couple years now, logging more than three billion hours of sleep, but the devices would only show wearers information on how long they slept. Now Fitbit will take motion data, along with heart rate variability, to show light, deep, and REM sleep stages. And the insights are supposed to draw a direct line between your daily activities and your sleep patterns, which has been, in theory, a kind of holy grail for these consumer wearables.

The new Alta HR costs $150, $20 more than last year’s Alta. It will ship in early April, around the same time the new sleep-tracking software rolls out to the Alta HR, the Charge 2 wristband, and the Blaze watch. Fitbit says it will continue to sell the older Alta wristband, the one that doesn’t track heart rate, as well as the Flex wristband and the Charge 2.

The new Alta HR wristband is coming at a challenging time for Fitbit. The company’s holiday quarter earnings were so disappointing that it prereleased its results in late January, and announced that it would be laying off more than 100 employees. At the same time, Fitbit is still considered the market leader in activity trackers.

There are a couple ways to look at this “new” Fitbit and sleep-tracking software. The first is that none of this is really new. The Alta HR form factor itself isn’t new; it’s the same wristband design from last year. Other companies, like Garmin and Xiaomi, also make thin activity-tracking wristbands with heart rate sensors, and Jawbone (while hardly a paradigm of consumer activity tracking these days) has offered detailed sleep tracking for years.

There’s also always the question of how accurate or effective these kinds of activity trackers are, or how long people actually wear them. Some studies in the past have found that they don’t necessarily help people lose weight, or that the sleep data they gather may be inaccurate.

There are still plenty of questions around how accurate these wearables are — and how long people wear them

Fitbit was also hit with a class action lawsuit early last year in which customers alleged that Fitbit’s heart rate tracking was inaccurate by a “significant margin,” especially during intense exercise. That litigation is still ongoing; Fitbit says its own extensive internal studies show that its tech meets industry expectations, with an average percent error of less than 6 percent.

On the upside for Fitbit: people seem to like buying Fitbits as long as they’re new; 70 percent of the company’s 2016 revenue came from sales of brand-new wearables. Analysts have been asking Fitbit whether the company was going to keep up a consistent product release cycle, and this may appease them, at least temporarily.

And, the fact that Fitbit managed to miniaturize its heart rate sensor technology, making it small enough to fit into the Alta wristband, points to Fitbit’s intentions of expanding into other product areas. It’s a given at this point that Fitbit is making a smartwatch, one that will likely support different apps, but CEO James Park has also said the company is exploring non-wrist-based gadgets.

Yuen, the director of R&D, said that shrinking the chip could also allow room for additional health sensors in future Fitbit products, though he declined to say exactly which health sensors the company is experimenting with.