The spaceplane conducted on-orbit experiments for 780 days during its mission, recently breaking its own record by being in orbit for more than two years. As of today, the total number of days spent on-orbit for the entire test vehicle program is 2,865 days.

https://www.af.mil/News/Article-Display/Article/1999734/x-37b-breaks-record-lands-after-780-days-in-orbit/ DoD News