Update the Min SDK version for the Auth0.Android SDK 26

[utkrishtsahu]

Changes

Updated the minimum SDK version from 21 (Android 5.0) to 26 (Android 8.0) and removed dead code paths that were only reachable on API < 23.

auth0/build.gradle

• minSdkVersion 21 → 26

sample/build.gradle

• minSdk 24 → 26

CryptoUtil.java

• Removed the legacy KeyPairGeneratorSpec branch (API 18-22) for RSA key generation. Only the KeyGenParameterSpec path (API 23+) remains.
• Removed unused imports: KeyguardManager, Intent, KeyPairGeneratorSpec
• Note: getKeyEntryCompat API < P check is kept — still needed for API 26-27

DPoPKeyStore.kt

• Removed dead if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M) throw check — always false with minSdk 26

BrowserPicker.java

• Simplified Build.VERSION.SDK_INT >= M ? MATCH_ALL : 0 to just MATCH_ALL
• Removed unused Build import

CryptoUtilTest.java

• Removed 3 legacy @config(sdk = 21) tests that tested the KeyPairGeneratorSpec path
• Renamed shouldCreateRSAKeyPairIfMissingOnAPI23AndUp → shouldCreateRSAKeyPairIfMissing

Auth0UserAgentTest.java

• Updated @config(sdk = 21/23) tests to use sdk = 28/30 (cached Robolectric jars)
• Replaced brittle hardcoded base64 assertions with decoded JSON assertions

V4_MIGRATION_GUIDE.md

• Added "Minimum SDK Version" section documenting the API 21 → 26 requirement change
• No public API changes. No endpoints added, deleted, or changed.

References

SDK-8577

Testing

Verified manually on emulator (API 34) with the sample app:

• ROPG login → Get Credentials → Get Credentials (Secure) → Delete Credentials

• Web Auth login → Get Credentials → Web Auth logout

• All flows use the simplified KeyGenParameterSpec and MATCH_ALL code paths

• Existing CryptoUtilTest and Auth0UserAgentTest updated to reflect the new minSdk. Legacy API 21 tests removed. All 1235 tests pass.

• Tested on API 34 emulator (Android 14), built with AGP 8.10.1, Gradle 8.11.1, Java 17

• Checklist

• I have read the Auth0 general contribution guidelines

• I have read the Auth0 Code of Conduct

• All existing and new tests complete without errors

[pmathew92]

We can now remove the DPoPException.UNSUPPORTED_ERROR and related code

[pmathew92]

Lets remove the DPoP UnsupportedError and related code. Also update the migration guide if required for the same