Yes, Stratus 1 and 1S receive traffic on the 978 MHz (UAT) frequency. Stratus 2, 2S, and 3 receive traffic on both the 978 MHz and 1090 MHz (ES) frequencies. The traffic you see on ForeFlight Mobile or on Stratus Insight is only ADS-B traffic. ADS-B traffic only includes the air-to-air traffic received directly from another aircraft and traffic rebroadcast to your aircraft from an ADS-B ground tower. Air-to-air traffic reports are only reported from ADS-B Out equipped aircraft. You will only receive ADS-B traffic from a ground tower if two things are true: 1) your aircraft, or another one nearby you, is ADS-B equipped, and 2) you are in communication with an ADS-B ground tower. Coverage varies based on your location as shown in the ADS-B coverage map. Remember, ADS-B traffic, even at its best, is not a complete picture of nearby traffic and is not a substitute for looking out the window when fulfilling your responsibility to see and avoid. Read this article from Sporty’s to learn more about how ADS-B traffic works. Read this article from ForeFlight to understand how traffic will appear on ForeFlight Mobile.