A new software system that will let people with diabetes customize their treatment and automatically adjust their insulin levels was just approved for use by the Food and Drug Administration. It will reach patients in January 2020.

The technology, called Control-IQ, is manufactured by Tandem Diabetes Care and connects with blood glucose sensors and insulin pumps to automatically increase, decrease, or stop the delivery of insulin in response to the glucose levels of people with Type 1 diabetes. People with Type 1 diabetes can’t produce their own insulin, which regulates blood sugar (aka glucose), so they need to take it from an external source every day. Currently, many patients with diabetes have to manually adjust and readjust the amount of insulin they receive throughout the day. With this kind of device, called a closed-loop system, users can instead rely on the device to adjust as needed.

People with Type 1 diabetes using Control-IQ with Tandem’s t:slim X2 insulin pump had fewer instances of high or low blood sugar than people manually adjusting the insulin, according to a six-month clinical trial recently published in The New England Journal of Medicine. Those patients also spent more time with blood sugar levels within their targeted range.

Other closed-loop systems have also gotten FDA approval. One central difference with this software is that it is considered “interoperable.” That means users are not locked into using products by Tandem Diabetes Care. They can build a personalized system using other sensors and pumps that have the same designation from the FDA.

Control-IQ can currently be used with Tandem Diabetes Care’s t:slim X2 insulin pump, which was approved as interoperable in February 2019, and Dexcom Inc’s G6 continuous glucose monitor, which was designated as interoperable in 2018.

The software system can also automatically deliver a corrective dose of fast-acting insulin if it determines that a user’s blood sugar levels are too high. That sets it apart from other closed-loop systems on the market, which deliver a continuous low dose of insulin, known as a basal rate, to keep blood sugar levels steady, but don’t automatically deliver corrective doses. Medical device company Medtronic, which had the first closed-loop system on the market, is now testing an addition of the same feature to their device.

People who use Tandem’s t:slim X2 insulin pump will automatically upgrade to the new system for free in January 2020.

Correction December 16th, 10:20AM ET: The story image has been updated with the Tandem product. A previous version of this story included an image of an insulin pump from a different company.