This is a fork of the official German <a href="https://www.coronawarn.app/en/">Corona-Warn-App</a> (CWA) without proprietary dependencies. While the app itself is Free Software, it depends on Google’s proprietary Exposure Notification Framework. This fork instead uses the drop-in compatible microg implementation. CCTG is fully compatible with the official app, including recording and sending tracing data as well as test submission and result collection.

<b>Tracing corona infections.</b> For contact tracing, the app collects short-lived IDs via bluetooth and broadcasts its own. In case of an infection, it allows to upload ones own IDs to a server using a TAN, allowing contacts to notice a match with their collected IDs and to be notified. All that happens without storing more data than necessary.

<b>Check in.</b> Another way of warning at-risk persons is by checking in to events and locations using CCTG. Hosts may use the app to generate a QR code that guests can scan. In case of an infection, users who were checked in at the same time or arrived shortly after the infected person left can be warned.

<b>Retrieve test results.</b> It is possible to receive test results for participating testing points both for PCR as well as rapid antigen tests. For the latter, it is additionally possible to generate a proof of the test result to be displayed through the app. To speed up registration at the rapid testing point, the app allows generating and storing a QR code that contains the personal data of the person to be tested.

<b>Vaccination.</b> The application can generate a proof of vaccination once a personal QR code issued by the point of vaccination is scanned.

Additionally, the app shows statistic cards regarding the rate of infections in Germany and provides a contact journal for manually entering people one has met.

<b>Transnational exposure logging.</b> Users outside of Germany can use the app and be warned about exposures in <a href="https://www.coronawarn.app/en/faq/#interoperability_countries">participating countries</a>, but they won't be able to retrieve test results through the app. In a positive PCR test result indicates an infection, they may <a href"https://www.coronawarn.app/en/faq/#test_in_other_country">call the TAN hotline</a> and enter the TAN within the app to warn their contacts.

<b>Lollipop support.</b> Android 5 is supported, however, Bluetooth drivers on older devices might not support a required feature for full support; see <a href="https://altbeacon.github.io/android-beacon-library/beacon-transmitter-devices.html">this list</a> for whether an old device supports this app. Not fully compatible devices will show a notice on the main screen.
