Can't build android app

hi there!
since the update to 4.18 (and android sdk update to api-27) i can’t build for older engine version. 4.18 is working but can’t build using 4.17 and 4.15.
i get the following error :


LogPlayLevel: ====11/5/2017 5:55:58 PM====UPDATING BUILD CONFIGURATION FILES====================================================
LogPlayLevel: **************************************************************************
LogPlayLevel: The "android" command is deprecated.
LogPlayLevel: For manual SDK, AVD, and project management, please use Android Studio.
LogPlayLevel: For command-line tools, use tools\bin\sdkmanager.bat
LogPlayLevel: and tools\bin\avdmanager.bat
LogPlayLevel: **************************************************************************
LogPlayLevel: Invalid or unsupported command "--silent update lib-project --path JavaLibs/downloader_library --target android-23"
LogPlayLevel: Supported commands are:
LogPlayLevel: android list target
LogPlayLevel: android list avd
LogPlayLevel: android list device
LogPlayLevel: android create avd
LogPlayLevel: android move avd
LogPlayLevel: android delete avd
LogPlayLevel: android list sdk
LogPlayLevel: android update sdk
LogPlayLevel: Program.Main: ERROR: AutomationTool terminated with exception: ERROR: C:/NVPACK2/android-sdk-windows/tools/android.bat failed with args --silent update lib-project --path JavaLibs/downloader_library --target android-23
LogPlayLevel: Program.Main: AutomationTool exiting with ExitCode=1 (Error_Unknown)
LogPlayLevel: Completed Launch On Stage: Deploy Task, Time: 4.504829
LogPlayLevel: BUILD FAILED
PackagingResults:Error: Error Launch failed! Unknown Error

i tried different API versions but it still doesn’t work .
thanks in advance !