diff --git a/buildSrc/src/main/kotlin/JvmConfig.kt b/buildSrc/src/main/kotlin/JvmConfig.kt
index ca3b3d1f14..351345000f 100644
--- a/buildSrc/src/main/kotlin/JvmConfig.kt
+++ b/buildSrc/src/main/kotlin/JvmConfig.kt
@@ -50,11 +50,12 @@ fun Project.configureJvm() {
         }
     }
 
+    val testJdk = project.testJdk
     val jvmTest = tasks.named<KotlinJvmTest>("jvmTest") {
         maxHeapSize = "2g"
         exclude("**/*StressTest*")
         useJUnitPlatform()
-        configureJavaToolchain(compileJdk)
+        configureJavaToolchain(compileJdk, testJdk)
     }
 
     tasks.register<Test>("stressTest") {
@@ -67,7 +68,7 @@ fun Project.configureJvm() {
         systemProperty("enable.stress.tests", "true")
         include("**/*StressTest*")
         useJUnitPlatform()
-        configureJavaToolchain(compileJdk)
+        configureJavaToolchain(compileJdk, testJdk)
     }
 
     val configuredVersion: String by rootProject.extra
@@ -83,14 +84,14 @@ fun Project.configureJvm() {
     }
 }
 
-/**
- * On local machine use for tests the JDK used for compilation.
- * On CI use the default JDK.
- */
-private fun Test.configureJavaToolchain(compileJdk: Int) {
-    val testJdk = if (CI) currentJdk else compileJdk
-    val javaToolchains = project.the<JavaToolchainService>()
+/** Configure tests against different JDK versions. */
+private fun Test.configureJavaToolchain(compileJdk: Int, testJdk: Int) {
+    if (testJdk < compileJdk) {
+        enabled = false
+        return
+    }
 
+    val javaToolchains = project.the<JavaToolchainService>()
     javaLauncher = javaToolchains.launcherFor {
         languageVersion = JavaLanguageVersion.of(testJdk)
     }
diff --git a/buildSrc/src/main/kotlin/KtorBuildProperties.kt b/buildSrc/src/main/kotlin/KtorBuildProperties.kt
index 38768aed4d..8450b18ace 100644
--- a/buildSrc/src/main/kotlin/KtorBuildProperties.kt
+++ b/buildSrc/src/main/kotlin/KtorBuildProperties.kt
@@ -16,7 +16,24 @@ val HOST_NAME = when {
     else -> error("Unknown os name `$OS_NAME`")
 }
 
-val currentJdk = JavaVersion.current().majorVersion.toInt()
+private var _testJdk = 0
+
+/**
+ * Retrieves the JDK version for running tests.
+ *
+ * Takes the version from property "test.jdk" or uses Gradle JDK by default.
+ * For example, to run tests against JDK 8, run test task with flag "-Ptest.jdk=8"
+ * or put this property to `gradle.properties`.
+ */
+val Project.testJdk: Int
+    get() {
+        if (_testJdk == 0) {
+            _testJdk = rootProject.properties["test.jdk"]?.toString()?.toInt()
+                ?: JavaVersion.current().majorVersion.toInt()
+            logger.info("Running tests against JDK $_testJdk")
+        }
+        return _testJdk
+    }
 
 val Project.requiredJdkVersion: Int
     get() = when {
diff --git a/gradle-settings-conventions/src/main/kotlin/conventions-dependency-resolution-management.settings.gradle.kts b/gradle-settings-conventions/src/main/kotlin/conventions-dependency-resolution-management.settings.gradle.kts
index 363b6addf9..27985787df 100644
--- a/gradle-settings-conventions/src/main/kotlin/conventions-dependency-resolution-management.settings.gradle.kts
+++ b/gradle-settings-conventions/src/main/kotlin/conventions-dependency-resolution-management.settings.gradle.kts
@@ -88,7 +88,7 @@ dependencyResolutionManagement {
 }
 
 fun VersionCatalogBuilder.downgradeTestDependencies() {
-    val testJdk = JavaVersion.current().majorVersion.toInt()
+    val testJdk = providers.gradleProperty("test.jdk").orNull?.toInt() ?: return
 
     if (testJdk < 11) version("logback", "1.3.14") // Java 8 support dropped in Logback 1.4.x
 }
diff --git a/ktor-client/ktor-client-tests/build.gradle.kts b/ktor-client/ktor-client-tests/build.gradle.kts
index 811f2d63e2..cf6c91fdbd 100644
--- a/ktor-client/ktor-client-tests/build.gradle.kts
+++ b/ktor-client/ktor-client-tests/build.gradle.kts
@@ -58,7 +58,7 @@ kotlin.sourceSets {
             api(project(":ktor-client:ktor-client-apache5"))
             runtimeOnly(project(":ktor-client:ktor-client-android"))
             runtimeOnly(project(":ktor-client:ktor-client-okhttp"))
-            if (currentJdk >= 11) {
+            if (testJdk >= 11) {
                 runtimeOnly(project(":ktor-client:ktor-client-java"))
             }
             implementation(project(":ktor-client:ktor-client-plugins:ktor-client-logging"))
diff --git a/settings.gradle.kts b/settings.gradle.kts
index b80d5536b7..eb60c53a47 100644
--- a/settings.gradle.kts
+++ b/settings.gradle.kts
@@ -24,8 +24,12 @@ include(":ktor-server:ktor-server-test-base")
 include(":ktor-server:ktor-server-test-suites")
 include(":ktor-server:ktor-server-jetty")
 include(":ktor-server:ktor-server-jetty:ktor-server-jetty-test-http2")
+include(":ktor-server:ktor-server-jetty-jakarta")
+include(":ktor-server:ktor-server-jetty-jakarta:ktor-server-jetty-test-http2-jakarta")
 include(":ktor-server:ktor-server-servlet")
+include(":ktor-server:ktor-server-servlet-jakarta")
 include(":ktor-server:ktor-server-tomcat")
+include(":ktor-server:ktor-server-tomcat-jakarta")
 include(":ktor-server:ktor-server-netty")
 include(":ktor-server:ktor-server-cio")
 include(":ktor-client")
@@ -40,15 +44,9 @@ include(":ktor-client:ktor-client-ios")
 include(":ktor-client:ktor-client-darwin")
 include(":ktor-client:ktor-client-darwin-legacy")
 include(":ktor-client:ktor-client-winhttp")
-if (JavaVersion.current() >= JavaVersion.VERSION_11) {
-    include(":ktor-client:ktor-client-java")
-    include(":ktor-client:ktor-client-jetty-jakarta")
-    include(":ktor-server:ktor-server-servlet-jakarta")
-    include(":ktor-server:ktor-server-jetty-jakarta")
-    include(":ktor-server:ktor-server-jetty-jakarta:ktor-server-jetty-test-http2-jakarta")
-    include(":ktor-server:ktor-server-tomcat-jakarta")
-}
+include(":ktor-client:ktor-client-java")
 include(":ktor-client:ktor-client-jetty")
+include(":ktor-client:ktor-client-jetty-jakarta")
 include(":ktor-client:ktor-client-js")
 include(":ktor-client:ktor-client-mock")
 include(":ktor-client:ktor-client-okhttp")