Can't build even change to sdk 24 in build.gradle

[David160601]

Launching lib\main.dart on sdk gphone64 x86 64 in debug mode... Running Gradle task 'assembleDebug'...

FAILURE: Build failed with an exception.

• What went wrong: Execution failed for task ':app:checkDebugDuplicateClasses'.

  A failure occurred while executing com.android.build.gradle.internal.tasks.CheckDuplicatesRunnable Duplicate class kotlin.collections.jdk8.CollectionsJDK8Kt found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk8-1.7.20 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.7.20) Duplicate class kotlin.internal.jdk7.JDK7PlatformImplementations found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk7-1.7.20 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.20) Duplicate class kotlin.internal.jdk7.JDK7PlatformImplementations$ReflectSdkVersion found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk7-1.7.20 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.20) Duplicate class kotlin.internal.jdk8.JDK8PlatformImplementations found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk8-1.7.20 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.7.20) Duplicate class kotlin.internal.jdk8.JDK8PlatformImplementations$ReflectSdkVersion found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk8-1.7.20 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.7.20) Duplicate class kotlin.io.path.DirectoryEntriesReader found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk7-1.7.20 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.20) Duplicate class kotlin.io.path.ExperimentalPathApi found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk7-1.7.20 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.20) Duplicate class kotlin.io.path.FileVisitorBuilder found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk7-1.7.20 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.20) Duplicate class kotlin.io.path.FileVisitorBuilderImpl found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk7-1.7.20 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.20) Duplicate class kotlin.io.path.FileVisitorImpl found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk7-1.7.20 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.20) Duplicate class kotlin.io.path.LinkFollowing found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk7-1.7.20 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.20) Duplicate class kotlin.io.path.PathNode found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk7-1.7.20 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.20) Duplicate class kotlin.io.path.PathRelativizer found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk7-1.7.20 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.20) Duplicate class kotlin.io.path.PathTreeWalk found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk7-1.7.20 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.20) Duplicate class kotlin.io.path.PathTreeWalk$bfsIterator$1 found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk7-1.7.20 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.20) Duplicate class kotlin.io.path.PathTreeWalk$dfsIterator$1 found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk7-1.7.20 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.20) Duplicate class kotlin.io.path.PathTreeWalkKt found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk7-1.7.20 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.20) Duplicate class kotlin.io.path.PathWalkOption found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk7-1.7.20 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.20) Duplicate class kotlin.io.path.PathsKt found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk7-1.7.20 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.20) Duplicate class kotlin.io.path.PathsKtPathReadWriteKt found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk7-1.7.20 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.20) Duplicate class kotlin.io.path.PathsKtPathUtilsKt found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk7-1.7.20 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.20) Duplicate class kotlin.jdk7.AutoCloseableKt found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk7-1.7.20 (org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.7.20) Duplicate class kotlin.jvm.jdk8.JvmRepeatableKt found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk8-1.7.20 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.7.20) Duplicate class kotlin.jvm.optionals.OptionalsKt found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk8-1.7.20 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.7.20) Duplicate class kotlin.random.jdk8.PlatformThreadLocalRandom found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk8-1.7.20 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.7.20) Duplicate class kotlin.streams.jdk8.StreamsKt found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk8-1.7.20 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.7.20) Duplicate class kotlin.streams.jdk8.StreamsKt$asSequence$$inlined$Sequence$1 found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk8-1.7.20 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.7.20) Duplicate class kotlin.streams.jdk8.StreamsKt$asSequence$$inlined$Sequence$2 found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk8-1.7.20 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.7.20) Duplicate class kotlin.streams.jdk8.StreamsKt$asSequence$$inlined$Sequence$3 found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk8-1.7.20 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.7.20) Duplicate class kotlin.streams.jdk8.StreamsKt$asSequence$$inlined$Sequence$4 found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk8-1.7.20 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.7.20) Duplicate class kotlin.text.jdk8.RegexExtensionsJDK8Kt found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk8-1.7.20 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.7.20) Duplicate class kotlin.time.jdk8.DurationConversionsJDK8Kt found in modules jetified-kotlin-stdlib-1.8.10 (org.jetbrains.kotlin:kotlin-stdlib:1.8.10) and jetified-kotlin-stdlib-jdk8-1.7.20 (org.jetbrains.kotlin:kotlin-stdlib-jdk8:1.7.20)

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BUILD FAILED in 2s Exception: Gradle task assembleDebug failed with exit code 1

[781flyingdutchman]

See issue #26: either your app or a library you are using is using an older version of the Kotlin standard libraries (and that is not compatible with the current version used in this package). See this comment (and the broader issue) to resolve. Closing this issue, as this is not an issue with the background_downloader package