NOTE: This scoping document is also available in German.
HINWEIS: Dieses Scoping-Dokument ist ebenfalls auf Deutsch verfügbar.
The aim of the Corona-Warn-App is to identify SARS-CoV-2 chains of infection as quickly as possible and to break them. It does this by rapidly and reliably notifying people that they have had contact with infected persons and therefore may have been exposed to the virus. These individuals can then self-isolate, to help stop the SARS-CoV-2 pandemic.
This document describes the functional requirements of the app’s design from a technical and process-based perspective. This version of the scope document describes the first release and an initial version of the app only.
The overall planning also foresees publishing other development documents, to solicit feedback from an early stage for potential incorporation in the project. The release architecture document and back-end alpha source code will be made available subsequently.
The requirements have been defined and outlined according to a person-centric methodology. This means the entire process flow is designed from the perspective of the people who use the app and the other stakeholders involved in the process. The aim is to map the needs of all stakeholders in such a way that it promotes a high degree of acceptance and makes the respective functions intuitive to use.
The interaction points and user experience are mapped based on a user journey. The resulting requirements are assigned to “epics”, or descriptions of the requirements at a high level of abstraction. These epics describe the individual contact points and general functions throughout the process that are required for usage and acceptance of the app. In turn, the epics are used to derive the detailed requirements in the form of user stories (software requirements formulated in everyday language). Through this approach, the individual requirements are structured as they are incorporated in the development process.
The following key usage profiles and stakeholders are integrated in the user journey, or overall process, and described in their roles:
All persons who use the app: Are notified of potential exposure to infected persons, verify their own test results, and then warn all the people they have encountered – voluntarily and under a pseudonym.
Provide support to persons who use the app by in answering questions about how to use the app, the technology, and data privacy. If asked, they provide information on proper conduct and where to get further information in case of contact or infection. Help verify and release test results in the app for infected individuals and can recommend that they contact their health department.
Provides epidemiological information and recommendations for using the app (content). Determines the parameters used to measure the number of contacts (to the extent of the API’s technical capabilities).
App usage is divided into different phases, based on contact points and interactions between people that occur successively. In each phase, persons are assigned motivations or requirements that meet their expectations of the app and guide them intuitively through the process.
In this phase, a person decides to get more information about the app. In this phase, persons may have different questions regarding usage of the app (application, data privacy, accessibility, and so on). It should be possible to have these questions answered before downloading the app (hotline, information on the websites of the RKI and Federal Ministry of Health (BMG), App Store/Google Play Store).
A person decides to download the app (App Store/Google Play Store) and, after the technical installation process, is given an introduction to the app the first time it is opened. In this introductory phase, app users are given an overview of the functionality, terms of use, and privacy provisions; are asked for the necessary consent; and guided through the notification and other settings.
The usage phase is subdivided into four further areas, in which people who use the app have different needs.
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Background
In idle mode, the application runs in the background on the smartphone and saves the pseudo IDs of other nearby app users, automatically and encrypted. At regular intervals, the app pulls from the server a list of pseudo IDs of the persons who have voluntarily reported that they are infected. The app compares their pseudo IDs with those stored on the smartphone to determine whether there has been any exposure.
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Exposure
If exposure to infected persons is determined, app user receives a notification and recommendations on what to do. For instance, that they should contact a medical professional or their responsible health department, and whether they should self-isolate.
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Testing
If an app user is tested for a SARS-CoV-2 infection, they can start the digital test information process in the app, which notifies them of their test result.
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Infection case
If an app user tests positive for SARS-CoV-2 infection, they can voluntarily publish the pseudonymized warn IDs saved in their app. That way, other app users can use their smartphones to find out whether they have been exposed to the infected user.
A person can uninstall the app at any time, completely deleting all the data stored in it.
The app functions are divided into user process phases (with direct ties to the user journey) and general support processes. An overview of the epics is depicted below:
| # | Epic | Description |
|---|---|---|
| 1 | Onboarding and Installation | All processes that take place the first time the app is used (such as consent, data privacy, language selection) |
| 2 | Information and Instructions for Using the App | Help tools for using the app (such as user manual, tutorial), as well as publication information for the app |
| 3 | Use in the Regular Process | App functions in idle mode (such as activate/deactivate, changing settings, monitoring app activities) |
| 4 | Exposure (Contact with an Infected Person) | All functions associated with contact points (such as notifications, recommended actions) |
| 5 | Notification of Covid-19 Test Results | Functions related to the notification of test results |
| 6 | Warning trigger | Process to trigger a warning if a test result is positive |
| # | Epic | Description |
|---|---|---|
| 7 | Parameter Settings | Parameters for contact point definition |
| 8 | Technical Support | Support processes (such as hotlines) |
| 9 | Accessibility | Apps from public authorities must be accessible, pursuant to the German Act on Equal Opportunities for Persons with Disabilities (BGG, section 12). Apps should be usable by all persons with disabilities. |
| 10 | Content Management | To adjust and update content in the app (texts, links, hotlines, and so on) |
The requirements the Corona-Warn-App must satisfy, and which define its functional scope, are formulated below in the usual format of a user story, unless specified otherwise:
"As <stakeholder>, I want <goal>, so that <reason>."
The corresponding acceptance criteria supplement the specification of the requirements by defining the conditions that the software must fulfill to satisfy user needs..
| # of user story ID | User story | Acceptance criteria |
|---|---|---|
| E01.01 | As an app user, the first time I launch the app, I want to receive an introduction to how it works (app motivation). | 1. An introduction to how the app works is displayed the first time the app is launched. 2. The introduction to how the app works is not displayed when the app is launched subsequently. 3. The explanatory content is available to app users in the respective functional areas. |
| E01.02 | As an app user, the first time I launch the app, I want to be notified about the terms of use and privacy provisions (data privacy screen) and grant my consent, so that I know how my data will be used within the app. | 1. By using the app, the user accepts the terms of use and privacy provisions. 2. The terms of use can be displayed within the app. 3. The consent prompt is shown only the first time a user launches the app. |
| E01.03 | As an app user, the first time I use the app, I want to be asked whether I consent to the creation of pseudonymized IDs and sending them to devices near me, so that I am informed about how the app works. | 1. Confirmation of the creation of pseudonymized IDs and their transmission to nearby devices by the app is a prerequisite for using the app. 2. The prompt no longer appears after the first time the app is used. |
| E01.04 | As an app user, the first time I use the app, I want to be asked whether the application can access the smartphone’s Bluetooth function, so that I can control how the app is used on the smartphone. | 1. This user story is tantamount to E01.03. The authorization to use the generation of pseudonymous IDs and send them to nearby devices is already contained in the usage of Bluetooth Low Energy (BLE). 2. The configuration of the general Bluetooth functions is only possible in the system settings. |
| E01.05 | As an app user, the first time I use the app, I want to be asked whether the application is allowed to send me notifications, so that I can get notifications in a variety of situations. | 1. The app’s notification settings are queried before the app is used for the first time. This enables local notifications. True push notifications from external servers are not supported (APNs/FCM). 2. The prompt no longer appears after the first time the app is used. |
| E01.06 | As an app user, I want the app to be displayed in my language the first time I use it, so that I can understand how to use the app. | 1. The configured system language is detected. 2. If the content is not available in the detected system language, English is selected by default. 3. The first version of the app is expected to be available also in languages other than English. |
| E01.07 | As an app user, I want to see help functions and settings for accessibility during the onboarding process, so that I can use the app. | 1. Accessibility is provided depending on the options available in the respective operating system. |
| # of user story ID | User story | Acceptance criteria |
|---|---|---|
| E02.01 | As an app user, I want to have access to a FAQ list, so that I can find answers to questions I might have about the app. | 1. The app will either contain a link to a web page with FAQs, which is displayed in a browser window, or the web page will be displayed within the app itself. |
| E02.02 | As an app user, I want to have access to instructions, so that I can understand the app and its functions. | 1. An explanation of the app’s various functions will be provided. |
| E02.03 | As an app user, I want to have access to an explanatory video, so that I can understand how to use the app and its functions. | 1. An explanation of the app’s various functions will be provided. |
| E02.04 | As an app user, I want to be able to display publication information for the app, so that I can see who is responsible for development and content of the app. | 1. There is a “Publication information” item in the menu. 2. The publication information contains the usual information required. |
| E02.05 | As an app user, I want to be able to display the terms of use and data privacy information at any time. | 1. The app provides simple access to the terms of use and data privacy information. |
| E02.06 | As an app user, I want to be able to see various hotlines for technical, privacy-related, health-related, and psychological questions, as well as for verification of test results, so that I can receive further information or answers to my questions. | 1. The app offers access to a technical hotline and a hotline for obtaining a phone TAN. 2. The times the hotline is available (such as 24/7) is displayed. 3. Phone numbers can be called directly from the app. |
| # of user story ID | User story | Acceptance criteria |
|---|---|---|
| E03.01 | As an app user, I want to be able to activate and deactivate the app, so that I can switch the functions on and off. | 1. The functions for generating pseudonymized IDs and sending them to nearby devices can be activated and deactivated. 2. The consequences of activation/deactivation are explained. |
| E03.02 | As an app user, I want to be able to reset to the app to the delivery defaults, so that I can reconfigure it. | 1. The app can be reset to the delivery defaults with a setting option. The saved traces have to be deleted through the system settings. |
| E03.03 | As an app user, I want to be able to adjust the app settings (access permissions, such as notifications) in a menu, so that I can manage the app functions and accesses. | 1. App users can call a menu for app settings. 2. Notifications can be activated and deactivated. 3. Access to the functions for generating pseudonymized IDs and sending them to nearby devices can be activated and deactivated. 4. Before access permissions are deactivated, I receive information as to which app functions will no longer work (in full). |
| # of user story ID | User story | Acceptance criteria |
|---|---|---|
| E04.01 | As an app user, I want to be notified when a person I have had contact with has reported an infection, so that I can then take the appropriate measures to stop the spread of the virus. | 1. Depending on the notification settings, the app sends a notification to the user. 2. If the risk assessment for a user changes, a notification informs users that there is news in the app. The actual changed risk assessment is not displayed until the app is opened. |
| E04.02 | As an app user, if I am exposed to the virus, I want to receive instructions from the app, so that I can adapt my behavior to RKI recommendations. | 1. A notification leads the user to the app. The recommendations from the RKI are defined statically in the app. |
| # of user story ID | User story | Acceptance criteria |
|---|---|---|
| E05.01 | As the RKI, I want only positively tested users to trigger a one-time warning, so that I can prevent misuse. | 1. Only positive tests can trigger a warning. This is ensured by the verification server and the hotline for the phone TAN procedure. 2. A warning can only be triggered once for each test. |
| E05.02 | As an app user, in case of a positive test result, I want to receive information about the illness and the necessary next steps, so that I can adapt my behavior to RKI recommendations. | 1. A notification merely informs you that there is news in the app. The test result itself can only be seen in the app. 2. An info text with defined content is displayed in the app (for example, information about the outcome of the test result, information about necessary measures, a hotline number). |
| # of user story ID | User story | Acceptance criteria |
|---|---|---|
| E06.01 | As an app user, I want to be able to scan a QR code provided by a medical professional or test center, so that I can receive my test result in the Corona-Warn-App. | 1. A QR code provided on a flyer from the medical professional or test center can be scanned with the Corona-Warn-App. 2. An explanatory text is displayed. |
| E06.02 | As an app user, I want to be notified within the Corona-Warn-App as soon as a test result becomes available. | 1. A notification merely informs you that there is news in the app. The test result itself can only be seen in the app. 2. The notification does not explicitly indicate whether the result is positive or negative. |
| E06.03 | As an app user, if I receive a positive test result, I want to be able to grant my consent to sending the pseudonymized IDs under which I was visible to other people in recent days to the Warn server, so that the people I have been in contact with can be warned by their apps. | 1. The IDs can be sent to the Warn server pseudonymized. 2. Data transmission is only possible if successfully verified beforehand. This is ensured by the verification server and the hotline for the phone TAN procedure. 3. Data transmission is only possible if the app user has granted consent beforehand. |
| E06.04 | As an app user, I want to be able to use a manual process (in addition to the digital process), for example, through a call center and without a QR code, to send the pseudonymized IDs under which I was visible to other app users in recent days, to the Warn server, so that the people I have been in contact with can be warned by their apps. | 1. The center responsible can generate a TAN and provide it to the person. (The TAN is generated by a server, not the call center itself.) |
| E06.05 | As an app user, I want to be able to enter a TAN in the app, so that I can use the TAN I have been given to assign my test result to my instance of the app. | 1. It is possible to enter a TAN within the app. 2. The app verifies the entered TAN and provides feedback as to whether it was correct (must be checked whether technically possible). |
| E06.06 | As an app user, after the TAN is verified, I want to share my pseudonymized IDs voluntarily, so that I can warn persons I may have been in contact with. | 1. The IDs can be sent to the Warn server pseudonymized. 2. Data transmission is only possible if successfully verified beforehand. This is ensured by the verification server and the hotline for the phone TAN procedure. 3. Data transmission is only possible if the person has granted consent beforehand. |
| # of user story ID | User story | Acceptance criteria |
|---|---|---|
| E07.01 | As the RKI, I want to be able to configure the parameters (to the extent the API is able to do this) for risk scoring, so that I can keep up with the latest research findings on virus transmission. | 1. Thresholds can be configured dependent on the provided API. 2. The app receives dynamic configurations from the RKI that can affect how the risk assessment is calculated. |
| # of user story ID | User story | Acceptance criteria |
|---|---|---|
| E08.01 | As an app user, I want to be able to contact a hotline, so that I can resolve any technical problems with the app. | 1. The phone number of the technical hotline is available in the app. |
| # of user story ID | User story | Acceptance criteria |
|---|---|---|
| E09.01 | As an app user, I want it to have audio output, so that I can use the app even if I have impaired vision (or am blind), for example. | 1. Accessibility regarding audio output is provided depending on the options available in the respective operating system. |
| E09.02 | As an app user, I want to have good contrast settings, modifiable font sizes, and an easily readable font, so that I can read the texts in the app easily. | 1. Accessibility regarding contrast and font size/type is provided depending on the options available in the respective operating system. |
| E09.03 | As an app user, I want to have the content in simplified language, so that I can easily understand how to use the app and why I should use it. | 1. The texts and languages are defined by the ordering party. |
| # of user story ID | User story | Acceptance criteria |
|---|---|---|
| E10.01 | As the RKI, I want to manage the app content centrally, so that I can update texts, links, hotlines, and so on once for all the places in the app. | 1. Content management will be carried out based on RKI requirements. 2. Content will be differentiated by static and dynamic content, in line with technical feasibility. 3. In the initial version, updates will be performed through an app update. |