android: Bump minSdkVersion to 23

.github/workflows/slow_tests.yml

@@ -158,12 +158,12 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        # 21 is our minimal API level
+        # 23 is our minimal API level
         # 33 is our target API level
         include:
-          - api_level: 21
+          - api_level: 23
             arch: x86
-          - api_level: 21
+          - api_level: 23
             arch: x86_64
           - api_level: 33
             arch: x86_64
@@ -211,7 +211,7 @@ jobs:
           api-level: ${{ matrix.api_level }}
           ndk: ${{ env.ANDROID_NDK_VERSION }}
           force-avd-creation: false
-          disk-size: 1024M
+          disk-size: 2048M
           emulator-options: -no-window -noaudio -no-boot-anim -no-metrics
           script: echo "Generated AVD snapshot for caching."
 
@@ -221,7 +221,7 @@ jobs:
           arch: ${{ matrix.arch }}
           api-level: ${{ matrix.api_level }}
           ndk: ${{ env.ANDROID_NDK_VERSION }}
-          disk-size: 1024M
+          disk-size: 2048M
           force-avd-creation: false
           emulator-options: -no-snapshot-save -no-window -noaudio -no-boot-anim -no-metrics
           script: |

CODING_GUIDELINES.md

@@ -81,7 +81,7 @@ These should usually be prioritized in that order, but adjust the trade-off as n
 
 # Java
 
-- Many of our APIs are shared between Android and Server, and we also run the client tests on desktop machines, so **stick to Java 8** unless you've verified that something newer is available on Android (back to our earliest supported version, API level 21, at the time of this writing), and don't use Android-specific APIs unless you're actually in Android-specific code. (This *should* be checked in CI but things have slipped through before, and it'll save you time to know whether you're allowed to use something.)
+- Many of our APIs are shared between Android and Server, and we also run the client tests on desktop machines, so **stick to Java 8** unless you've verified that something newer is available on Android (back to our earliest supported version, API level 23, at the time of this update), and don't use Android-specific APIs unless you're actually in Android-specific code. (This *should* be checked in CI but things have slipped through before, and it'll save you time to know whether you're allowed to use something.)
 
 - **Put server-specific APIs in the server/ folder if they're not needed to test client features**, so they don't add code size for Android.
 

RELEASE_NOTES.md

@@ -3,3 +3,5 @@ v0.86.0
 - Node: export libsignal-net remote config keys as an array.
 
 - java: Remove protocol.util.Pair in favor of kotlin.Pair
+
+- Android: The min SDK version is now 23.

TESTING.md

@@ -42,7 +42,7 @@ Rust allows running tests with cross-compiled targets, but normally that only wo
     ANDROID_NDK_HOME=path/to/ndk
     CARGO_PROFILE_TEST_STRIP=debuginfo   # make the "push" step take less time
     CARGO_PROFILE_BENCH_STRIP=debuginfo  # same for benchmarks
-    CARGO_TARGET_AARCH64_LINUX_ANDROID_LINKER=path/to/ndk/toolchains/llvm/prebuilt/YOUR_HOST_HERE/bin/aarch64-linux-android21-clang
+    CARGO_TARGET_AARCH64_LINUX_ANDROID_LINKER=path/to/ndk/toolchains/llvm/prebuilt/YOUR_HOST_HERE/bin/aarch64-linux-android23-clang
     CARGO_TARGET_AARCH64_LINUX_ANDROID_RUNNER=bin/adb-run-test # in the repo root
     ```
 

java/android/benchmarks/build.gradle

@@ -13,7 +13,7 @@ android {
     compileSdk 34
 
     defaultConfig {
-        minSdkVersion 21
+        minSdkVersion 23
         targetSdkVersion 33
         multiDexEnabled true
 

java/android/build.gradle

@@ -22,7 +22,7 @@ android {
     ndkVersion '28.0.13004108'
 
     defaultConfig {
-        minSdkVersion 21
+        minSdkVersion 23
         targetSdkVersion 33
         multiDexEnabled true
         testInstrumentationRunner "org.signal.libsignal.util.AndroidJUnitRunner"

java/android/packaging-test/build.gradle

@@ -12,7 +12,7 @@ android {
     compileSdk 34
 
     defaultConfig {
-        minSdkVersion 21
+        minSdkVersion 23
         targetSdkVersion 33
         multiDexEnabled true
 

java/build_jni.sh

@@ -188,10 +188,11 @@ export CARGO_PROFILE_RELEASE_CODEGEN_UNITS=1
 
 # Use the Android NDK's prebuilt Clang+lld as pqcrypto's compiler and Rust's linker.
 ANDROID_TOOLCHAIN_DIR=$(echo "${ANDROID_NDK_HOME}/toolchains/llvm/prebuilt"/*/bin/)
-export CC_aarch64_linux_android="${ANDROID_TOOLCHAIN_DIR}/aarch64-linux-android21-clang"
-export CC_armv7_linux_androideabi="${ANDROID_TOOLCHAIN_DIR}/armv7a-linux-androideabi21-clang"
-export CC_x86_64_linux_android="${ANDROID_TOOLCHAIN_DIR}/x86_64-linux-android21-clang"
-export CC_i686_linux_android="${ANDROID_TOOLCHAIN_DIR}/i686-linux-android21-clang"
+ANDROID_MIN_SDK_VERSION=23
+export CC_aarch64_linux_android="${ANDROID_TOOLCHAIN_DIR}/aarch64-linux-android${ANDROID_MIN_SDK_VERSION}-clang"
+export CC_armv7_linux_androideabi="${ANDROID_TOOLCHAIN_DIR}/armv7a-linux-androideabi${ANDROID_MIN_SDK_VERSION}-clang"
+export CC_x86_64_linux_android="${ANDROID_TOOLCHAIN_DIR}/x86_64-linux-android${ANDROID_MIN_SDK_VERSION}-clang"
+export CC_i686_linux_android="${ANDROID_TOOLCHAIN_DIR}/i686-linux-android${ANDROID_MIN_SDK_VERSION}-clang"
 
 export CARGO_TARGET_AARCH64_LINUX_ANDROID_LINKER="${CC_aarch64_linux_android}"
 export CARGO_TARGET_ARMV7_LINUX_ANDROIDEABI_LINKER="${CC_armv7_linux_androideabi}"