Versioning is a critical component of your app upgrade and maintenance strategy. Versioning is important because:
- Users need to have specific information about the app version that is installed on their devices and the upgrade versions available for installation.
- Other apps—including other apps that you publish as a suite—need to query the system for your app's version to determine compatibility and identify dependencies.
- Services where you publish your app(s) may also need to query your app for its version so that they can display the version to users. A publishing service may also need to check the app version to determine compatibility and establish upgrade/downgrade relationships.
The Android system uses your app's version information to protect against downgrades. The system doesn't use app version information to enforce restrictions on upgrades or compatibility of third-party apps. Your app must enforce any version restrictions and tell users about them.
The Android system enforces system version compatibility, as expressed
    by the minSdk setting in the build files. This setting
    lets an app specify the minimum system API that it is compatible with.
    For more information about API requirements,
    see Specify API level (SDK version) requirements.
Versioning requirements vary between different projects. However, many developers consider Semantic Versioning a good basis for a versioning strategy.
Set app version information
To define the version information for your app, set values for the version settings in the Gradle build files:
Groovy
android { namespace 'com.example.testapp' compileSdk 33 defaultConfig { applicationId "com.example.testapp" minSdk 24 targetSdk 33 versionCode 1 versionName "1.0" ... } ... } ...
Kotlin
android { namespace = "com.example.testapp" compileSdk = 33 defaultConfig { applicationId = "com.example.testapp" minSdk = 24 targetSdk = 33 versionCode = 1 versionName = "1.0" ... } ... } ...
Version settings
Define values for both of the version settings available: versionCode and
    versionName.
  
- versionCode
- A positive integer used as an internal version number.
    This number helps determine whether one version is more recent
    than another, with higher numbers indicating more recent versions. This is
    not the version number shown to users; that number is set by the
    versionNamesetting. The Android system uses theversionCodevalue to protect against downgrades by preventing users from installing an APK with a lowerversionCodethan the version currently installed on their device.The value is a positive integer so that other apps can programmatically evaluate it—to check an upgrade or downgrade relationship, for instance. You can set the value to any positive integer. However, make sure that each successive release of your app uses a greater value. Note: The greatest value Google Play allows for versionCodeis 2100000000.You can't upload an APK to the Play Store with a versionCodeyou have already used for a previous version.Note: In some situations, you might want to upload a version of your app with a lower versionCodethan the most recent version. For example, if you are publishing multiple APKs, you might have pre-setversionCoderanges for specific APKs. For more about assigningversionCodevalues for multiple APKs, see Assigning version codes.Typically, you release the first version of your app with versionCodeset to 1, then monotonically increase the value with each release, regardless of whether the release constitutes a major or minor release. This means that theversionCodevalue doesn't necessarily resemble the app release version that is visible to the user. Apps and publishing services shouldn't display this version value to users.
- versionName
- A string used as the version number shown to users. This setting can be specified as a raw string or as a reference to a string resource. - The value is a string so that you can describe the app version as a <major>.<minor>.<point> string or as any other type of absolute or relative version identifier. The - versionNameis the only value displayed to users.
Define version values
    You can define default values for these settings by including them in the
    defaultConfig {} block, nested inside the android {}
    block of your module's build.gradle or build.gradle.kts file. You can
    then override these default values for different versions of your app by defining separate
    values for individual build types or product flavors. The following file shows the
    versionCode and versionName settings in the
    defaultConfig {} block, as well as the productFlavors {} block.
  
These values are then merged into your app's manifest file during the build process.
Groovy
android { ... defaultConfig { ... versionCode 2 versionName "1.1" } productFlavors { demo { ... versionName "1.1-demo" } full { ... } } }
Kotlin
android { ... defaultConfig { ... versionCode = 2 versionName = "1.1" } productFlavors { create("demo") { ... versionName = "1.1-demo" } create("full") { ... } } }
      In the defaultConfig {} block of this example, the
      versionCode value indicates that the current APK contains the
      second release of the app, and the versionName string specifies
      that it will appear to users as version 1.1. This file also defines two product flavors,
      "demo" and "full." Since the "demo" product flavor defines versionName as
      "1.1-demo", the "demo" build uses this versionName instead of the default value.
      The "full" product flavor block doesn't define versionName, so it
      uses the default value of "1.1".
    
      Note: If your app defines the app version directly in the
    <manifest> element, the version values in the Gradle build
    file override the settings in the manifest. Additionally, defining these
    settings in the Gradle build files lets you specify different values for
    different versions of your app. For greater flexibility and to avoid
    potential overwriting when the manifest is merged, remove these
    attributes from the <manifest> element and define your
    version settings in the Gradle build files instead.
  
The Android framework provides an API to let you query the system
    for version information about your app. To obtain version information,
    use the
    
      PackageManager.getPackageInfo(java.lang.String, int) method.
    
Specify API level (SDK version) requirements
If your app requires a specific minimum version of the Android
platform, you can specify that version requirement as API level settings
  in the app's build.gradle or build.gradle.kts file. During the build
  process, these settings are merged into your app's manifest file. Specifying API level
  requirements ensures that your app can only be installed on devices that are
  running a compatible version of the Android platform. 
  Note: If you specify API level requirements directly in your
  app's manifest file, the corresponding settings in the build files will
  override the settings in the manifest file. Additionally, defining these
  settings in the Gradle build files lets you specify different values for
  different versions of your app. For greater flexibility and to avoid
  potential overwriting when the manifest is merged, remove these
  attributes from the <uses-sdk> element and define your API
  level settings in the Gradle build files instead.
There are two API level settings available:
- minSdk— The minimum version of the Android platform on which the app will run, specified by the platform's API level identifier.
- targetSdk— The API level, tied to the- <SDK_INT>constant, on which the app is designed to run. In some cases, this allows the app to use manifest elements or behaviors defined in the target API level, rather than being restricted to using only those defined for the minimum API level.
It is not possible to specify that an app either targets or requires
a minor SDK version. To call new APIs safely that require a higher major
or minor SDK version than your minSdkVersion, you can guard
a code block with a check for a minor or major release using the
SDK_INT_FULL constant.
if (SDK_INT_FULL >= VERSION_CODES_FULL.[MAJOR or MINOR RELEASE]) { // Use APIs introduced in a major or minor SDK version }
  To specify default API level requirements in a build.gradle or
  build.gradle.kts file, add one or more of the API level settings to the
  defaultConfig{} block, nested inside the android {} block. You can
  also  override these default values for different
  versions of your app by adding the settings to build types or product flavors.
  The following file specifies default
  minSdk and targetSdk settings in the
  defaultConfig {} block and overrides minSdk
  for one product flavor:
Groovy
android { ... defaultConfig { ... minSdk 21 targetSdk 33 } productFlavors { main { ... } afterNougat { ... minSdk 24 } } }
Kotlin
android { ... defaultConfig { ... minSdk = 21 targetSdk = 33 } productFlavors { create("main") { ... } create("afterNougat") { ... minSdk = 24 } } }
When preparing to install your app, the system checks the value of
  these settings and compares them to the system version. If the
minSdk value is greater than the system version, the
system prevents the installation of the app.
If you don't specify these settings, the system assumes that your app is
  compatible with all platform versions. This is equivalent to setting minSdk to 
  1.
For more information, see What is API Level?. For Gradle build settings, see Configure build variants.
