diff --git a/build.gradle b/build.gradle
index 9dd9e74517..1bec7a3700 100644
--- a/build.gradle
+++ b/build.gradle
@@ -3,7 +3,9 @@
  */
 
 
+import org.jetbrains.kotlin.config.KotlinCompilerVersion
 import org.jetbrains.kotlin.gradle.plugin.KotlinPlatformType
+import org.jetbrains.kotlin.gradle.tasks.AbstractKotlinCompile
 import org.jetbrains.kotlin.konan.target.HostManager
 import org.jetbrains.dokka.gradle.DokkaTaskPartial
 
@@ -54,6 +56,7 @@ buildscript {
         classpath "org.jetbrains.kotlinx:kotlinx-knit:$knit_version"
         classpath "com.moowork.gradle:gradle-node-plugin:$gradle_node_version"
         classpath "org.jetbrains.kotlinx:binary-compatibility-validator:$binary_compatibility_validator_version"
+        classpath "ru.vyarus:gradle-animalsniffer-plugin:1.5.3" // Android API check
 
         // JMH plugins
         classpath "com.github.jengelman.gradle.plugins:shadow:5.1.0"
@@ -101,6 +104,8 @@ allprojects {
 }
 
 apply plugin: "binary-compatibility-validator"
+apply plugin: 'base'
+
 apiValidation {
     ignoredProjects += unpublished + ["kotlinx-coroutines-bom"]
     if (build_snapshot_train) {
@@ -126,7 +131,7 @@ allprojects {
 // Add dependency to core source sets. Core is configured in kx-core/build.gradle
 configure(subprojects.findAll { !sourceless.contains(it.name) && it.name != coreModule }) {
     evaluationDependsOn(":$coreModule")
-    if (it.name in multiplatform) {
+    if (isMultiplatform(it)) {
         apply plugin: "kotlin-multiplatform"
         apply from: rootProject.file("gradle/compile-jvm-multiplatform.gradle")
         apply from: rootProject.file("gradle/compile-common.gradle")
@@ -162,8 +167,8 @@ configure(subprojects.findAll { !sourceless.contains(it.name) }) {
     apply plugin: 'kotlinx-atomicfu'
 
     // Configure options for all Kotlin compilation tasks
-    tasks.withType(org.jetbrains.kotlin.gradle.tasks.AbstractKotlinCompile).all {
-        kotlinOptions.freeCompilerArgs += OptInPresetKt.optInAnnotations.collect { "-Xopt-in=" + it }
+    tasks.withType(AbstractKotlinCompile).all {
+        kotlinOptions.freeCompilerArgs += OptInPreset.optInAnnotations.collect { "-Xopt-in=" + it }
         kotlinOptions.freeCompilerArgs += "-progressive"
         // Disable KT-36770 for RxJava2 integration
         kotlinOptions.freeCompilerArgs += "-XXLanguage:-ProhibitUsingNullableTypeParameterAgainstNotNullAnnotated"
@@ -207,7 +212,7 @@ if (build_snapshot_train) {
 
 // Redefine source sets because we are not using 'kotlin/main/fqn' folder convention
 configure(subprojects.findAll {
-    !sourceless.contains(it.name) && !multiplatform.contains(it.name) &&
+    !sourceless.contains(it.name) && !isMultiplatform(it) &&
             it.name != "benchmarks" &&
             it.name != "example-frontend-js"
 }) {
@@ -262,7 +267,7 @@ configure(subprojects.findAll { !unpublished.contains(it.name) }) {
     }
 
     List<String> jarTasks
-    if (it.name in multiplatform) {
+    if (isMultiplatform(it)) {
         jarTasks = ["jvmJar", "metadataJar"]
     } else if (it.name == "kotlinx-coroutines-debug") {
         // We shadow debug module instead of just packaging it
@@ -282,7 +287,7 @@ configure(subprojects.findAll { !unpublished.contains(it.name) }) {
 }
 
 // Report Kotlin compiler version when building project
-println("Using Kotlin compiler version: $org.jetbrains.kotlin.config.KotlinCompilerVersion.VERSION")
+println("Using Kotlin compiler version: $KotlinCompilerVersion.VERSION")
 
 // --------------- Cache redirector ---------------
 
@@ -296,7 +301,7 @@ def publishTasks = getTasksByName("publish", true) + getTasksByName("publishNpm"
 
 task deploy(dependsOn: publishTasks)
 
-apply plugin: 'base'
+apply plugin: 'animalsniffer-convention'
 
 clean.dependsOn gradle.includedBuilds.collect { it.task(':clean') }
 
diff --git a/buildSrc/build.gradle.kts b/buildSrc/build.gradle.kts
index c54e226af1..c2808c004a 100644
--- a/buildSrc/build.gradle.kts
+++ b/buildSrc/build.gradle.kts
@@ -46,4 +46,5 @@ dependencies {
     implementation(kotlin("gradle-plugin", version("kotlin")))
     implementation("org.jetbrains.dokka:dokka-gradle-plugin:${version("dokka")}")
     implementation("org.jetbrains.dokka:dokka-core:${version("dokka")}")
+    implementation("ru.vyarus:gradle-animalsniffer-plugin:1.5.3") // Android API check
 }
diff --git a/buildSrc/src/main/kotlin/OptInPreset.kt b/buildSrc/src/main/kotlin/OptInPreset.kt
index ee2aab11cf..fdcdb8ecf8 100644
--- a/buildSrc/src/main/kotlin/OptInPreset.kt
+++ b/buildSrc/src/main/kotlin/OptInPreset.kt
@@ -1,6 +1,7 @@
 /*
  * Copyright 2016-2021 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
  */
+@file:JvmName("OptInPreset")
 
 val optInAnnotations = listOf(
     "kotlin.RequiresOptIn",
@@ -10,4 +11,4 @@ val optInAnnotations = listOf(
     "kotlinx.coroutines.ExperimentalCoroutinesApi",
     "kotlinx.coroutines.ObsoleteCoroutinesApi",
     "kotlinx.coroutines.InternalCoroutinesApi",
-    "kotlinx.coroutines.FlowPreview")
\ No newline at end of file
+    "kotlinx.coroutines.FlowPreview")
diff --git a/buildSrc/src/main/kotlin/Projects.kt b/buildSrc/src/main/kotlin/Projects.kt
index d5494e16cd..d19e00ca46 100644
--- a/buildSrc/src/main/kotlin/Projects.kt
+++ b/buildSrc/src/main/kotlin/Projects.kt
@@ -2,7 +2,7 @@
  * Copyright 2016-2021 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
  */
 @file:JvmName("Projects")
-import org.gradle.api.Project
+import org.gradle.api.*
 
 fun Project.version(target: String): String =
     property("${target}_version") as String
@@ -18,3 +18,14 @@ val internal = setOf("kotlinx.coroutines", "benchmarks", "integration-testing")
 val unpublished = internal + setOf("example-frontend-js", "android-unit-tests")
 
 val Project.isMultiplatform: Boolean get() = name in multiplatform
+
+// Projects that we do not check for Android API level 14 check due to various limitations
+val androidNonCompatibleProjects = setOf(
+    "kotlinx-coroutines-debug",
+    "kotlinx-coroutines-swing",
+    "kotlinx-coroutines-javafx",
+    "kotlinx-coroutines-jdk8",
+    "kotlinx-coroutines-jdk9",
+    "kotlinx-coroutines-reactor",
+    "kotlinx-coroutines-test"
+)
diff --git a/buildSrc/src/main/kotlin/animalsniffer-convention.gradle.kts b/buildSrc/src/main/kotlin/animalsniffer-convention.gradle.kts
new file mode 100644
index 0000000000..32b4931e57
--- /dev/null
+++ b/buildSrc/src/main/kotlin/animalsniffer-convention.gradle.kts
@@ -0,0 +1,27 @@
+/*
+ * Copyright 2016-2021 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
+ */
+
+import ru.vyarus.gradle.plugin.animalsniffer.*
+
+subprojects {
+    // Skip JDK 8 projects or unpublished ones
+    if (!shouldSniff()) return@subprojects
+    apply(plugin = "ru.vyarus.animalsniffer")
+    configure<AnimalSnifferExtension> {
+        sourceSets = listOf((project.extensions.getByName("sourceSets") as SourceSetContainer).getByName("main"))
+    }
+    val signature: Configuration by configurations
+    dependencies {
+        signature("net.sf.androidscents.signature:android-api-level-14:4.0_r4@signature")
+        signature("org.codehaus.mojo.signature:java17:1.0@signature")
+    }
+}
+
+fun Project.shouldSniff(): Boolean {
+    // Skip all non-JVM projects
+    if (platformOf(project) != "jvm") return false
+    val name = project.name
+    if (name in unpublished || name in sourceless || name in androidNonCompatibleProjects) return false
+    return true
+}
diff --git a/buildSrc/src/main/kotlin/kotlin-jvm-conventions.gradle.kts b/buildSrc/src/main/kotlin/kotlin-jvm-conventions.gradle.kts
index c7744f8702..90847f4567 100644
--- a/buildSrc/src/main/kotlin/kotlin-jvm-conventions.gradle.kts
+++ b/buildSrc/src/main/kotlin/kotlin-jvm-conventions.gradle.kts
@@ -11,8 +11,8 @@ plugins {
 }
 
 java {
-    sourceCompatibility = JavaVersion.VERSION_1_6
-    targetCompatibility = JavaVersion.VERSION_1_6
+    sourceCompatibility = JavaVersion.VERSION_1_8
+    targetCompatibility = JavaVersion.VERSION_1_8
 }
 
 dependencies {
diff --git a/gradle/compile-jvm-multiplatform.gradle b/gradle/compile-jvm-multiplatform.gradle
index 5e65042746..88b717976d 100644
--- a/gradle/compile-jvm-multiplatform.gradle
+++ b/gradle/compile-jvm-multiplatform.gradle
@@ -2,12 +2,16 @@
  * Copyright 2016-2021 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
  */
 
-sourceCompatibility = 1.6
-targetCompatibility = 1.6
+sourceCompatibility = 1.8
+targetCompatibility = 1.8
 
 kotlin {
     jvm {}
     sourceSets {
+        jvmMain.dependencies {
+            compileOnly "org.codehaus.mojo:animal-sniffer-annotations:1.20"
+        }
+
         jvmTest.dependencies {
             api "org.jetbrains.kotlin:kotlin-test:$kotlin_version"
             // Workaround to make addSuppressed work in tests
diff --git a/kotlinx-coroutines-core/build.gradle b/kotlinx-coroutines-core/build.gradle
index 4435ad7fa1..fdb6f39787 100644
--- a/kotlinx-coroutines-core/build.gradle
+++ b/kotlinx-coroutines-core/build.gradle
@@ -90,6 +90,11 @@ kotlin {
             }
         }
     }
+
+    jvm {
+        // For animal sniffer
+        withJava()
+    }
 }
 
 configurations {
diff --git a/kotlinx-coroutines-core/common/src/flow/SharingStarted.kt b/kotlinx-coroutines-core/common/src/flow/SharingStarted.kt
index f4c6f2ee8d..a5ae63667f 100644
--- a/kotlinx-coroutines-core/common/src/flow/SharingStarted.kt
+++ b/kotlinx-coroutines-core/common/src/flow/SharingStarted.kt
@@ -5,7 +5,7 @@
 package kotlinx.coroutines.flow
 
 import kotlinx.coroutines.*
-import kotlinx.coroutines.flow.internal.*
+import kotlinx.coroutines.internal.IgnoreJreRequirement
 import kotlin.time.*
 
 /**
@@ -204,5 +204,6 @@ private class StartedWhileSubscribed(
             stopTimeout == other.stopTimeout &&
             replayExpiration == other.replayExpiration
 
+    @IgnoreJreRequirement // desugared hashcode implementation
     override fun hashCode(): Int = stopTimeout.hashCode() * 31 + replayExpiration.hashCode()
 }
diff --git a/kotlinx-coroutines-core/common/src/internal/InternalAnnotations.common.kt b/kotlinx-coroutines-core/common/src/internal/InternalAnnotations.common.kt
new file mode 100644
index 0000000000..1df81c9cc4
--- /dev/null
+++ b/kotlinx-coroutines-core/common/src/internal/InternalAnnotations.common.kt
@@ -0,0 +1,10 @@
+/*
+ * Copyright 2016-2021 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
+ */
+
+package kotlinx.coroutines.internal
+
+// Ignore JRE requirements for animal-sniffer, compileOnly dependency
+@Target(AnnotationTarget.FUNCTION, AnnotationTarget.TYPE)
+@OptionalExpectation
+internal expect annotation class IgnoreJreRequirement()
diff --git a/kotlinx-coroutines-core/common/src/internal/Symbol.kt b/kotlinx-coroutines-core/common/src/internal/Symbol.kt
index 84db2ef6cc..b629951fbd 100644
--- a/kotlinx-coroutines-core/common/src/internal/Symbol.kt
+++ b/kotlinx-coroutines-core/common/src/internal/Symbol.kt
@@ -4,12 +4,14 @@
 
 package kotlinx.coroutines.internal
 
+import kotlin.jvm.*
+
 /**
  * A symbol class that is used to define unique constants that are self-explanatory in debugger.
  *
  * @suppress **This is unstable API and it is subject to change.**
  */
-internal class Symbol(val symbol: String) {
+internal class Symbol(@JvmField val symbol: String) {
     override fun toString(): String = "<$symbol>"
 
     @Suppress("UNCHECKED_CAST", "NOTHING_TO_INLINE")
diff --git a/kotlinx-coroutines-core/jvm/src/CoroutineContext.kt b/kotlinx-coroutines-core/jvm/src/CoroutineContext.kt
index 4864c0abd6..d562207f8b 100644
--- a/kotlinx-coroutines-core/jvm/src/CoroutineContext.kt
+++ b/kotlinx-coroutines-core/jvm/src/CoroutineContext.kt
@@ -5,7 +5,6 @@
 package kotlinx.coroutines
 
 import kotlinx.coroutines.internal.*
-import kotlinx.coroutines.scheduling.*
 import kotlin.coroutines.*
 import kotlin.coroutines.jvm.internal.CoroutineStackFrame
 
@@ -159,6 +158,7 @@ internal actual val CoroutineContext.coroutineName: String? get() {
 
 private const val DEBUG_THREAD_NAME_SEPARATOR = " @"
 
+@IgnoreJreRequirement // desugared hashcode implementation
 internal data class CoroutineId(
     val id: Long
 ) : ThreadContextElement<String>, AbstractCoroutineContextElement(CoroutineId) {
diff --git a/kotlinx-coroutines-core/jvm/src/debug/AgentPremain.kt b/kotlinx-coroutines-core/jvm/src/debug/AgentPremain.kt
index d592bf657a..4b0ce3f31e 100644
--- a/kotlinx-coroutines-core/jvm/src/debug/AgentPremain.kt
+++ b/kotlinx-coroutines-core/jvm/src/debug/AgentPremain.kt
@@ -6,6 +6,7 @@ package kotlinx.coroutines.debug
 
 import android.annotation.*
 import kotlinx.coroutines.debug.internal.*
+import org.codehaus.mojo.animal_sniffer.*
 import sun.misc.*
 import java.lang.instrument.*
 import java.lang.instrument.ClassFileTransformer
@@ -17,6 +18,7 @@ import java.security.*
  */
 @Suppress("unused")
 @SuppressLint("all")
+@IgnoreJRERequirement // Never touched on Android
 internal object AgentPremain {
 
     private val enableCreationStackTraces = runCatching {
diff --git a/kotlinx-coroutines-core/jvm/src/internal/InternalAnnotations.kt b/kotlinx-coroutines-core/jvm/src/internal/InternalAnnotations.kt
new file mode 100644
index 0000000000..41707f7b89
--- /dev/null
+++ b/kotlinx-coroutines-core/jvm/src/internal/InternalAnnotations.kt
@@ -0,0 +1,8 @@
+/*
+ * Copyright 2016-2021 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
+ */
+
+package kotlinx.coroutines.internal
+
+@Suppress("ACTUAL_WITHOUT_EXPECT") // Not the same name to WA the bug in the compiler
+internal actual typealias IgnoreJreRequirement = org.codehaus.mojo.animal_sniffer.IgnoreJRERequirement