Stopp Corona is the national contact tracing app of Austria. Stopp Corona in its first iteration was released prior to the GAEN API. The code is open source on GitHub. While it was not built on the GAEN API, its decentralized Bluetooth design aimed to maintain similar DP-3T values. The Stopp Corona website advertises a commitment to data security by emphasizing that the app does not collect any additional information until you have a positive diagnosis. Following a positive diagnosis, the Austrian Government and Austrian Red Cross would record your phone number and keep it for up to 30 days. The app would notify the contacts of an infected user who made contact up to 48 hours before they input their diagnosis and ask them to self-isolate. The alerts were split into Red (severe) and Yellow (autionary) warnings for if you were diagnosed or have a suspicion, respectively. In order to generate a Yellow warning, you would have to tell the app that you suffer from a recurring dry cough and/or temperature of 38 degrees (C) or higher. Green signal (all clear) can be sent to contacts who receive a Yellow warning if the original user gets a negative test. In June 2020, Stopp Corona switched to the GAEN API. Users exchange anonymized keys via bluetooth when their phones come into close proximity. The user can choose if they want the keys to be exchanged automaticaly or manually. If a user suspects they have, or have been diagnosed with COVID-19, the proximity information is uploaded do a decentralized database and alerts are sent out to those who they have exchanged keys with.