A digital health company still in a stealthy mode, has added more than $3 million to the $2.5 million in equity it has raised since 2015.

Durham-based R65 Labs, Inc., the startup launched by former Modality founder Dr. Mark Williams, has raised a $3 million equity round, according to a regulatory filing, adding the to more than $2.5 million the company previously raised.

In an employment posting, the company described itself as: “R65 Labs is an early-stage digital health company committed to solving problems where health, education, technology and user experience intersect.”

The firm’s web site says only: “Prologue.”

Williams, a neuroscientist, medical educator and recipient of the Apple Award for Innovation in Science launched with a focus on mobile educational technology in 2006. It was one of only 12 firms selected by Steve Jobs to present at the Apple App Store launch in 2008.

Mobile reference technology firm Epocrates bought the company in 2008 after Modality earned intertional exposure with apps sold through Apple’s app store. The firm built some 150 applications.

The company disclosed the latest equity raise in a filing with the U.S. Securities and Exchange Commission.