Here are some things we need to document in README.

For user - what are requirements

• For desktop - range of supported JDK versions needed when building the project from sources.

• Minimum Java version (build and run-time) - what is it and where it is defined.

  • roc-java/build.gradle

    Lines 18 to 19 in b309665

    	sourceCompatibility = 1.8
    	targetCompatibility = 1.8

  • roc-java/android/roc-android/build.gradle

    Lines 41 to 42 in b309665

    	sourceCompatibility JavaVersion.VERSION_1_8
    	targetCompatibility JavaVersion.VERSION_1_8

• Minimum Android version - what is level, what is corresponding OS version, and where it is defined.

  • roc-java/android/roc-android/build.gradle

    Line 26 in b309665

    minSdkVersion 26

For developer - what versions to bump

roc-java developers should periodically bump the following versions to the latest available:

• SDK API level (SDK_LEVEL) (sets compileSdkVersion and targetSdkVersion)
• Android NDK version (NDK_VERSION)
• Android build-tools version (BUILD_TOOLS_VERSION)
• CMake version (CMAKE_VERSION)

All these versions are defined in build.yml as described in detail in this issue: #105. We can include some info and links from that issue to README.

See also #112. ROC_VERSION will also need periodical bump.

I think we should also mention android_docker.sh, which has its own set of defaults. These defaults are used if the user did not specify any variables when building AAR locally.