Merge pull request #443 from corona-warn-app/docs/federation

fix: update backend service to include EFGS

cwa-versioning.md

@@ -14,7 +14,7 @@ We plan to never deprecate outdated API versions. That means that even on MAJOR
 
 Backend components will always remain compatible due to ongoing the availability of old API versions.
 
-To ensure that all clients use the current "state of the art" information in order to apply the respective algorithms the cwa-server component can deprecate older Android and iOS app versions. The current minimum required app versions can be viewed in the [App Version Config](https://github.com/corona-warn-app/cwa-server/blob/master/services/distribution/src/main/resources/master-config/app-version-config.yaml).
+To ensure that all clients use the current "state of the art" information in order to apply the respective algorithms the cwa-server component can deprecate older Android and iOS app versions. The current minimum required app versions can be viewed in the [App Version Config](https://github.com/corona-warn-app/cwa-server/blob/master/services/distribution/src/main/resources/application.yaml#L93).
 The `app-version-config` is checked by the mobile clients on a regular basis. When the client detects that the required `min` version is higher than the current installed version, the user will be notified about the need to update the app. The app will not be useable until this update is performed.
 
 ## Changelogs

solution_architecture.md

@@ -117,12 +117,18 @@ The Corona-Warn-App Server needs to fulfill the following tasks:
   - Threshold values for [attenuation buckets](#attenuation-buckets)
   - Risk scores for defined values
   - Threshold values for risk categories and alerts
+  - Valid country codes for EFGS Visited Countries
 - On a regular schedule (e.g. hourly)
   - Assemble diagnosis keys into chunks for a given time period
   - Store chunks as static files (in protocol buffers, compatible with the format specified by Apple and Google)
   - Transfer files to a storage service as shown at the bottom of *Figure 6* which acts as a source for the Content Delivery Network (CDN)
+- Handle the integration with the [European Federation Gateway Service](https://github.com/eu-federation-gateway-service/efgs-federation-gateway) which consists of:
+  - Downloading keys which are shared from connected countries and making them available for use by the CWA Mobile applications
+  - Upload relevant keys for DE to the service to share with other connected countries
+  - Expose a callback API which can be used by the EFGS to notify CWA when new key batches are available for download
+  - Handle the translation of keys values for DSOS and TRL
 
-Those tasks are visualized in *Figure 7*. Each of swim lanes (vertical sections of the diagram) on the left side (Phone 1, Phone 2, Phone n) represent one device that has the Corona-Warn-App installed. The user of Phone 1 has taken a SARS-CoV-2 test (which comes back positive later). The users of Phone 2 and Phone n only use the functionality to trace potential exposure.
+Those tasks relevant for interaction with the CWA Mobile application are visualized in *Figure 7*. Each of swim lanes (vertical sections of the diagram) on the left side (Phone 1, Phone 2, Phone n) represents one device that has the Corona-Warn-App installed. The user of Phone 1 has taken a SARS-CoV-2 test (which comes back positive later). The users of Phone 2 and Phone n only use the functionality to trace potential exposure.
 The Corona-Warn-App Server represents the outside picture of the individual service working in the back end. For a better understanding, the database has been visualized separately.
 
 ![Figure 7: Interaction of the mobile application(s) with the back-end servers and CDN](images/solution_architecture/figure_7.svg "Figure 7: Interaction of the mobile application(s) with the back-end servers and CDN")