diff --git a/src/funcTest/groovy/info/solidsoft/gradle/pitest/functional/AbstractPitestFunctionalSpec.groovy b/src/funcTest/groovy/info/solidsoft/gradle/pitest/functional/AbstractPitestFunctionalSpec.groovy
index 253c6a0e..048da906 100644
--- a/src/funcTest/groovy/info/solidsoft/gradle/pitest/functional/AbstractPitestFunctionalSpec.groovy
+++ b/src/funcTest/groovy/info/solidsoft/gradle/pitest/functional/AbstractPitestFunctionalSpec.groovy
@@ -71,6 +71,10 @@ abstract class AbstractPitestFunctionalSpec extends IntegrationSpec {
 
     //TODO: Switch to Gradle mechanism once upgraded to 6.x
     protected boolean isJava13Compatible() {
-        return System.getProperty("java.version").startsWith("13") || System.getProperty("java.version").startsWith("14")
+        return System.getProperty("java.version").startsWith("13") || isJava14Compatible()
+    }
+
+    protected boolean isJava14Compatible() {
+        return System.getProperty("java.version").startsWith("14") || System.getProperty("java.version").startsWith("15")
     }
 }
diff --git a/src/funcTest/groovy/info/solidsoft/gradle/pitest/functional/PitestPluginGradleVersionFunctionalSpec.groovy b/src/funcTest/groovy/info/solidsoft/gradle/pitest/functional/PitestPluginGradleVersionFunctionalSpec.groovy
index 1931b598..6a81badc 100644
--- a/src/funcTest/groovy/info/solidsoft/gradle/pitest/functional/PitestPluginGradleVersionFunctionalSpec.groovy
+++ b/src/funcTest/groovy/info/solidsoft/gradle/pitest/functional/PitestPluginGradleVersionFunctionalSpec.groovy
@@ -32,6 +32,8 @@ class PitestPluginGradleVersionFunctionalSpec extends AbstractPitestFunctionalSp
     private static final GradleVersion MINIMAL_SUPPORTED_JAVA12_COMPATIBLE_GRADLE_VERSION = PitestPlugin.MINIMAL_SUPPORTED_GRADLE_VERSION
     //6.0+ - https://github.com/gradle/gradle/issues/8681#issuecomment-532507276
     private static final GradleVersion MINIMAL_SUPPORTED_JAVA13_COMPATIBLE_GRADLE_VERSION = GradleVersion.version("6.0.1")
+    //6.3+ - https://github.com/gradle/gradle/issues/10248
+    private static final GradleVersion MINIMAL_SUPPORTED_JAVA14_COMPATIBLE_GRADLE_VERSION = GradleVersion.version("6.3-rc-1")
 
     void setup() {
         daemonMaxIdleTimeInSecondsInMemorySafeMode = 1  //trying to mitigate "Gradle killed" issues with Travis
@@ -90,7 +92,7 @@ class PitestPluginGradleVersionFunctionalSpec extends AbstractPitestFunctionalSp
     //TODO: Extract regression tests control mechanism to a separate class (or even better trait) when needed in some other place
     private static final String REGRESSION_TESTS_ENV_NAME = "PITEST_REGRESSION_TESTS"
     private static final List<String> GRADLE5_VERSIONS = ["5.6.1", "5.6"]
-    private static final List<String> GRADLE6_VERSIONS = ["6.2.1", "6.1.1", MINIMAL_SUPPORTED_JAVA13_COMPATIBLE_GRADLE_VERSION.version]
+    private static final List<String> GRADLE6_VERSIONS = ["6.3-rc-1", "6.2.1", "6.1.1", MINIMAL_SUPPORTED_JAVA13_COMPATIBLE_GRADLE_VERSION.version]
     private static final List<String> GRADLE_LATEST_VERSIONS = [GRADLE5_VERSIONS.first(), GRADLE6_VERSIONS.first()]
 
     private List<String> resolveRequestedGradleVersions() {
@@ -117,8 +119,9 @@ class PitestPluginGradleVersionFunctionalSpec extends AbstractPitestFunctionalSp
             //All supported versions should be Java 8 compatible
             return requestedGradleVersions
         }
-        GradleVersion minimalCompatibleGradleVersion = !isJava13Compatible() ? MINIMAL_SUPPORTED_JAVA12_COMPATIBLE_GRADLE_VERSION :
-            MINIMAL_SUPPORTED_JAVA13_COMPATIBLE_GRADLE_VERSION
+        GradleVersion minimalCompatibleGradleVersion = !isJava14Compatible() ? MINIMAL_SUPPORTED_JAVA13_COMPATIBLE_GRADLE_VERSION :
+            !isJava13Compatible() ? MINIMAL_SUPPORTED_JAVA12_COMPATIBLE_GRADLE_VERSION :
+                MINIMAL_SUPPORTED_JAVA14_COMPATIBLE_GRADLE_VERSION
         return leaveJavaXCompatibleGradleVersionsOnly(requestedGradleVersions, minimalCompatibleGradleVersion)
     }
 
diff --git a/src/funcTest/groovy/info/solidsoft/gradle/pitest/functional/PitestPluginPitVersionFunctionalSpec.groovy b/src/funcTest/groovy/info/solidsoft/gradle/pitest/functional/PitestPluginPitVersionFunctionalSpec.groovy
index f3eeb8cd..967a4177 100644
--- a/src/funcTest/groovy/info/solidsoft/gradle/pitest/functional/PitestPluginPitVersionFunctionalSpec.groovy
+++ b/src/funcTest/groovy/info/solidsoft/gradle/pitest/functional/PitestPluginPitVersionFunctionalSpec.groovy
@@ -12,6 +12,7 @@ class PitestPluginPitVersionFunctionalSpec extends AbstractPitestFunctionalSpec
     private static final String MINIMAL_JAVA10_COMPATIBLE_PIT_VERSION = "1.4.0"
     private static final String MINIMAL_JAVA11_COMPATIBLE_PIT_VERSION = "1.4.2" //in fact 1.4.1, but 1.4.2 is also Java 12 compatible
     private static final String MINIMAL_JAVA13_COMPATIBLE_PIT_VERSION = "1.4.6" //not officially, but at least simple case works
+    private static final String MINIMAL_JAVA14_COMPATIBLE_PIT_VERSION = "1.4.11" //not officially, but with ASM 7.3.1
 
     def "setup and run pitest task with PIT #pitVersion"() {
         given:
@@ -35,10 +36,13 @@ class PitestPluginPitVersionFunctionalSpec extends AbstractPitestFunctionalSpec
             result.standardOutput.contains('Generated 2 mutations Killed 1 (50%)')
             result.standardOutput.contains('Ran 2 tests (1 tests per mutation)')
         where:
-            pitVersion << getPitVersionsCompoatibleWithCurrentJavaVersion().unique() //be aware that unique() is available since Groovy 2.4.0
+            pitVersion << getPitVersionsCompatibleWithCurrentJavaVersion().unique() //be aware that unique() is available since Groovy 2.4.0
     }
 
-    private List<String> getPitVersionsCompoatibleWithCurrentJavaVersion() {
+    private List<String> getPitVersionsCompatibleWithCurrentJavaVersion() {
+        if (isJava14Compatible()) {
+            return [PitestPlugin.DEFAULT_PITEST_VERSION, MINIMAL_JAVA14_COMPATIBLE_PIT_VERSION]
+        }
         if (isJava13Compatible()) {
             return [PitestPlugin.DEFAULT_PITEST_VERSION, MINIMAL_JAVA13_COMPATIBLE_PIT_VERSION]
         }