diff --git a/build-tools-internal/src/integTest/groovy/org/elasticsearch/gradle/internal/InternalDistributionDownloadPluginFuncTest.groovy b/build-tools-internal/src/integTest/groovy/org/elasticsearch/gradle/internal/InternalDistributionDownloadPluginFuncTest.groovy
index c7643da1c73b9..57f4fd6d7f625 100644
--- a/build-tools-internal/src/integTest/groovy/org/elasticsearch/gradle/internal/InternalDistributionDownloadPluginFuncTest.groovy
+++ b/build-tools-internal/src/integTest/groovy/org/elasticsearch/gradle/internal/InternalDistributionDownloadPluginFuncTest.groovy
@@ -51,7 +51,7 @@ class InternalDistributionDownloadPluginFuncTest extends AbstractGradleFuncTest
     def "resolves expanded bwc versions from source"() {
         given:
         internalBuild()
-        bwcMajor1ProjectSetup()
+        bwcProjectSetup("major1")
         buildFile << """
             apply plugin: 'elasticsearch.internal-distribution-download'
 
@@ -81,7 +81,7 @@ class InternalDistributionDownloadPluginFuncTest extends AbstractGradleFuncTest
     def "fails on resolving bwc versions with no bundled jdk"() {
         given:
         internalBuild()
-        bwcMajor1ProjectSetup()
+        bwcProjectSetup("major1")
         buildFile << """
             apply plugin: 'elasticsearch.internal-distribution-download'
 
@@ -105,12 +105,47 @@ class InternalDistributionDownloadPluginFuncTest extends AbstractGradleFuncTest
                 "without a bundled JDK is not supported.")
     }
 
-    private void bwcMajor1ProjectSetup() {
+    def "resolves detached version from source"() {
+        given:
+        internalBuild()
+        bwcProjectSetup("main")
+        buildFile << """
+            apply plugin: 'elasticsearch.internal-distribution-download'
+
+            System.setProperty("tests.bwc.main.version", "9.2.0")
+
+            elasticsearch_distributions {
+              test_distro {
+                  version = "9.2.0"
+                  type = "archive"
+                  platform = "linux"
+                  architecture = Architecture.current();
+                  detachedVersion = true
+              }
+            }
+
+            tasks.register("setupDistro", Sync) {
+                from(elasticsearch_distributions.test_distro)
+                into("build/distro")
+            }
+        """
+
+        when:
+        def result = gradleRunner("setupDistro").build()
+
+        then:
+        result.task(":distribution:bwc:main:buildBwcExpandedTask").outcome == TaskOutcome.SUCCESS
+        result.task(":setupDistro").outcome == TaskOutcome.SUCCESS
+        assertExtractedDistroIsCreated("distribution/bwc/main/build/install/elastic-distro",
+            'bwc-marker.txt')
+    }
+
+    private void bwcProjectSetup(String bwcProjectName) {
         settingsFile << """
-        include ':distribution:bwc:major1'
+        include ':distribution:bwc:$bwcProjectName'
         """
-        def bwcSubProjectFolder = testProjectDir.newFolder("distribution", "bwc", "major1")
-        new File(bwcSubProjectFolder, 'bwc-marker.txt') << "bwc=major1"
+        def bwcSubProjectFolder = testProjectDir.newFolder("distribution", "bwc", bwcProjectName)
+        new File(bwcSubProjectFolder, 'bwc-marker.txt') << "bwc=$bwcProjectName"
         new File(bwcSubProjectFolder, 'build.gradle') << """
             apply plugin:'base'
 
diff --git a/build-tools-internal/src/main/groovy/elasticsearch.bc-upgrade-test.gradle b/build-tools-internal/src/main/groovy/elasticsearch.bc-upgrade-test.gradle
index 94702c840c745..568201ca11130 100644
--- a/build-tools-internal/src/main/groovy/elasticsearch.bc-upgrade-test.gradle
+++ b/build-tools-internal/src/main/groovy/elasticsearch.bc-upgrade-test.gradle
@@ -11,8 +11,18 @@ import org.elasticsearch.gradle.Version
 import org.elasticsearch.gradle.testclusters.StandaloneRestIntegTestTask
 
 tasks.register("bcUpgradeTest", StandaloneRestIntegTestTask) {
-  // We use a phony version here as the real version is provided via `tests.bwc.main.version` system property
-  usesBwcDistribution(Version.fromString("0.0.0"))
-  systemProperty("tests.old_cluster_version", "0.0.0")
-  onlyIf("tests.bwc.main.version system property exists") { System.getProperty("tests.bwc.main.version") != null }
+  project.gradle.taskGraph.whenReady { allTasks ->
+    if (allTasks.hasTask(getPath())) {
+      if (System.getProperty("tests.bwc.refspec.main") == null) {
+        throw new GradleException("You must set the `tests.bwc.refspec.main` system property to run bcUpgradeTest")
+      }
+      if (System.getProperty("tests.bwc.main.version") == null) {
+        throw new GradleException("You must set the `tests.bwc.main.version` system property to run bcUpgradeTest")
+      }
+    }
+  }
+  if (System.getProperty("tests.bwc.refspec.main") != null && System.getProperty("tests.bwc.main.version") != null) {
+    usesBwcDistributionFromRef(System.getProperty("tests.bwc.refspec.main"), Version.fromString(System.getProperty("tests.bwc.main.version")))
+    systemProperty("tests.old_cluster_version", System.getProperty("tests.bwc.main.version"))
+  }
 }
diff --git a/build-tools-internal/src/main/java/org/elasticsearch/gradle/internal/InternalDistributionDownloadPlugin.java b/build-tools-internal/src/main/java/org/elasticsearch/gradle/internal/InternalDistributionDownloadPlugin.java
index f32afa1641e2e..809089c7b0b5c 100644
--- a/build-tools-internal/src/main/java/org/elasticsearch/gradle/internal/InternalDistributionDownloadPlugin.java
+++ b/build-tools-internal/src/main/java/org/elasticsearch/gradle/internal/InternalDistributionDownloadPlugin.java
@@ -74,7 +74,7 @@ public void apply(Project project) {
      */
     private void registerInternalDistributionResolutions(List<DistributionResolution> resolutions, Provider<BwcVersions> bwcVersions) {
         resolutions.add(new DistributionResolution("local-build", (project, distribution) -> {
-            if (isCurrentVersion(distribution)) {
+            if (isCurrentVersion(distribution) && distribution.isDetachedVersion() == false) {
                 // non-external project, so depend on local build
                 return new ProjectBasedDistributionDependency(
                     config -> projectDependency(project.getDependencies(), distributionProjectPath(distribution), config)
@@ -86,7 +86,7 @@ private void registerInternalDistributionResolutions(List<DistributionResolution
         resolutions.add(new DistributionResolution("bwc", (project, distribution) -> {
             BwcVersions.UnreleasedVersionInfo unreleasedInfo = bwcVersions.get()
                 .unreleasedInfo(Version.fromString(distribution.getVersion()));
-            if (unreleasedInfo != null) {
+            if (unreleasedInfo != null && distribution.isDetachedVersion() == false) {
                 if (distribution.getBundledJdk() == false) {
                     throw new GradleException(
                         "Configuring a snapshot bwc distribution ('"
@@ -103,21 +103,17 @@ private void registerInternalDistributionResolutions(List<DistributionResolution
             return null;
         }));
 
-        // Distribution resolution for "override" versions. This allows for building from source for any version, including the current
+        // Distribution resolution for "detached" versions. This allows for building from source for any version, including the current
         // version of existing released versions from a commit form the main branch. This is done by passing certain system properties, ex:
         //
         // -Dtests.bwc.refspec.main=deadbeef -Dtests.bwc.main.version=9.0.0
         //
-        // The 'test.bwc.main.version' property should map to the version returned by the commit referenced in 'tests.bwc.refspec.main'.
-        resolutions.add(new DistributionResolution("override", (project, distribution) -> {
-            String versionProperty = System.getProperty("tests.bwc.main.version");
-            // We use this phony version as a placeholder for the real version
-            if (distribution.getVersion().equals("0.0.0")) {
-                if (versionProperty == null) {
-                    throw new GradleException("System property 'tests.bwc.main.version' expected for building bwc version.");
-                }
+        // The distribution version set by 'test.bwc.main.version' property should map to the version returned by the commit
+        // referenced in 'tests.bwc.refspec.main'.
+        resolutions.add(new DistributionResolution("detached", (project, distribution) -> {
+            if (distribution.isDetachedVersion()) {
                 BwcVersions.UnreleasedVersionInfo unreleasedVersionInfo = new BwcVersions.UnreleasedVersionInfo(
-                    Version.fromString(versionProperty),
+                    Version.fromString(distribution.getVersion()),
                     "main",
                     ":distribution:bwc:main"
                 );
diff --git a/build-tools-internal/src/main/java/org/elasticsearch/gradle/internal/test/rest/RestTestBasePlugin.java b/build-tools-internal/src/main/java/org/elasticsearch/gradle/internal/test/rest/RestTestBasePlugin.java
index b7d7ce62774ce..5e3b8edb912dd 100644
--- a/build-tools-internal/src/main/java/org/elasticsearch/gradle/internal/test/rest/RestTestBasePlugin.java
+++ b/build-tools-internal/src/main/java/org/elasticsearch/gradle/internal/test/rest/RestTestBasePlugin.java
@@ -106,13 +106,15 @@ public void apply(Project project) {
         ElasticsearchDistribution defaultDistro = createDistribution(
             project,
             DEFAULT_REST_INTEG_TEST_DISTRO,
-            VersionProperties.getElasticsearch()
+            VersionProperties.getElasticsearch(),
+            false
         );
         ElasticsearchDistribution integTestDistro = createDistribution(
             project,
             INTEG_TEST_REST_INTEG_TEST_DISTRO,
             VersionProperties.getElasticsearch(),
-            ElasticsearchDistributionTypes.INTEG_TEST_ZIP
+            ElasticsearchDistributionTypes.INTEG_TEST_ZIP,
+            false
         );
 
         // Create configures for module and plugin dependencies
@@ -238,21 +240,11 @@ public Void call(Object... args) {
                     }
 
                     Version version = (Version) args[0];
-                    boolean isReleased = bwcVersions.unreleasedInfo(version) == null && version.toString().equals("0.0.0") == false;
+                    boolean isReleased = bwcVersions.unreleasedInfo(version) == null;
                     String versionString = version.toString();
-                    ElasticsearchDistribution bwcDistro = createDistribution(project, "bwc_" + versionString, versionString);
-
-                    if (jdkIsIncompatibleWithOS(Version.fromString(versionString))) {
-                        var toolChainService = project.getExtensions().getByType(JavaToolchainService.class);
-                        var fallbackJdk17Launcher = toolChainService.launcherFor(spec -> {
-                            spec.getVendor().set(JvmVendorSpec.ADOPTIUM);
-                            spec.getLanguageVersion().set(JavaLanguageVersion.of(17));
-                        });
-                        task.environment(
-                            "ES_FALLBACK_JAVA_HOME",
-                            fallbackJdk17Launcher.get().getMetadata().getInstallationPath().getAsFile().getPath()
-                        );
-                    }
+                    ElasticsearchDistribution bwcDistro = createDistribution(project, "bwc_" + versionString, versionString, false);
+
+                    handleJdkIncompatibleWithOS(version, project, task);
                     task.dependsOn(bwcDistro);
                     registerDistributionInputs(task, bwcDistro);
 
@@ -261,16 +253,63 @@ public Void call(Object... args) {
                         providerFactory.provider(() -> bwcDistro.getExtracted().getSingleFile().getPath())
                     );
 
-                    if (version.getMajor() > 0 && version.before(bwcVersions.getMinimumWireCompatibleVersion())) {
+                    if (version.before(bwcVersions.getMinimumWireCompatibleVersion())) {
                         // If we are upgrade testing older versions we also need to upgrade to 7.last
                         this.call(bwcVersions.getMinimumWireCompatibleVersion());
                     }
                     return null;
                 }
             });
+
+            task.getExtensions().getExtraProperties().set("usesBwcDistributionFromRef", new Closure<Void>(task) {
+                @Override
+                public Void call(Object... args) {
+                    if (args.length != 2 || args[0] instanceof String == false || args[1] instanceof Version == false) {
+                        throw new IllegalArgumentException("Expected arguments (String refSpec, org.elasticsearch.gradle.Version version)");
+                    }
+
+                    String refSpec = (String) args[0];
+                    Version version = (Version) args[1];
+                    boolean isDetachedVersion = true;
+                    String versionString = version.toString();
+
+                    ElasticsearchDistribution bwcDistro = createDistribution(project, "bwc_" + refSpec, versionString, isDetachedVersion);
+                    handleJdkIncompatibleWithOS(version, project, task);
+
+                    task.dependsOn(bwcDistro);
+                    registerDistributionInputs(task, bwcDistro);
+
+                    nonInputSystemProperties.systemProperty(
+                        BWC_SNAPSHOT_DISTRIBUTION_SYSPROP_PREFIX + versionString,
+                        providerFactory.provider(() -> bwcDistro.getExtracted().getSingleFile().getPath())
+                    );
+                    return null;
+                }
+            });
         });
     }
 
+    /**
+     * Older distributions ship with openjdk versions that are not compatible with newer kernels of ubuntu 24.04 and later
+     * Therefore we pass explicitly the runtime java to use the adoptium jdk that is maintained longer and compatible
+     * with newer kernels.
+     * 8.10.4 is the last version shipped with jdk < 21. We configure these cluster to run with jdk 17 adoptium as 17 was
+     * the last LTS release before 21
+     */
+    private static void handleJdkIncompatibleWithOS(Version version, Project project, StandaloneRestIntegTestTask task) {
+        if (jdkIsIncompatibleWithOS(version)) {
+            var toolChainService = project.getExtensions().getByType(JavaToolchainService.class);
+            var fallbackJdk17Launcher = toolChainService.launcherFor(spec -> {
+                spec.getVendor().set(JvmVendorSpec.ADOPTIUM);
+                spec.getLanguageVersion().set(JavaLanguageVersion.of(17));
+            });
+            task.environment(
+                "ES_FALLBACK_JAVA_HOME",
+                fallbackJdk17Launcher.get().getMetadata().getInstallationPath().getAsFile().getPath()
+            );
+        }
+    }
+
     private void copyDependencies(Project project, DependencySet dependencies, Configuration configuration) {
         configuration.getDependencies()
             .stream()
@@ -279,16 +318,23 @@ private void copyDependencies(Project project, DependencySet dependencies, Confi
             .forEach(dependencies::add);
     }
 
-    private ElasticsearchDistribution createDistribution(Project project, String name, String version) {
-        return createDistribution(project, name, version, null);
+    private ElasticsearchDistribution createDistribution(Project project, String name, String version, boolean detachedVersion) {
+        return createDistribution(project, name, version, null, detachedVersion);
     }
 
-    private ElasticsearchDistribution createDistribution(Project project, String name, String version, ElasticsearchDistributionType type) {
+    private ElasticsearchDistribution createDistribution(
+        Project project,
+        String name,
+        String version,
+        ElasticsearchDistributionType type,
+        boolean detachedVersion
+    ) {
         NamedDomainObjectContainer<ElasticsearchDistribution> distributions = DistributionDownloadPlugin.getContainer(project);
         ElasticsearchDistribution maybeDistro = distributions.findByName(name);
         if (maybeDistro == null) {
             return distributions.create(name, distro -> {
                 distro.setVersion(version);
+                distro.setDetachedVersion(detachedVersion);
                 distro.setArchitecture(Architecture.current());
                 if (type != null) {
                     distro.setType(type);
diff --git a/build-tools/src/main/java/org/elasticsearch/gradle/ElasticsearchDistribution.java b/build-tools/src/main/java/org/elasticsearch/gradle/ElasticsearchDistribution.java
index 3f9669af0568b..94d373cc59add 100644
--- a/build-tools/src/main/java/org/elasticsearch/gradle/ElasticsearchDistribution.java
+++ b/build-tools/src/main/java/org/elasticsearch/gradle/ElasticsearchDistribution.java
@@ -49,6 +49,7 @@ public String toString() {
 
     private final Property<Architecture> architecture;
     private final Property<String> version;
+    private final Property<Boolean> detachedVersion;
     private final Property<ElasticsearchDistributionType> type;
     private final Property<Platform> platform;
     private final Property<Boolean> bundledJdk;
@@ -69,6 +70,7 @@ public String toString() {
         this.configuration = fileConfiguration;
         this.architecture = objectFactory.property(Architecture.class);
         this.version = objectFactory.property(String.class).convention(VersionProperties.getElasticsearch());
+        this.detachedVersion = objectFactory.property(Boolean.class).convention(false);
         this.type = objectFactory.property(ElasticsearchDistributionType.class);
         this.type.convention(ElasticsearchDistributionTypes.ARCHIVE);
         this.platform = objectFactory.property(Platform.class);
@@ -91,6 +93,19 @@ public void setVersion(String version) {
         this.version.set(version);
     }
 
+    /**
+     * Informs if the version is not tied to any Elasticsearch release and is a custom build.
+     * This is true when the distribution is not from HEAD but also not any known released version.
+     * In that case the detached source build needs to be prepared by `usedBwcDistributionFromRef(ref, version)`.
+     */
+    public boolean isDetachedVersion() {
+        return detachedVersion.get();
+    }
+
+    public void setDetachedVersion(boolean detachedVersion) {
+        this.detachedVersion.set(detachedVersion);
+    }
+
     public Platform getPlatform() {
         return platform.getOrNull();
     }
diff --git a/modules/ingest-geoip/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/ingest/geoip/FullClusterRestartIT.java b/modules/ingest-geoip/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/ingest/geoip/FullClusterRestartIT.java
index a82b236c01aaa..0f68547ecbd76 100644
--- a/modules/ingest-geoip/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/ingest/geoip/FullClusterRestartIT.java
+++ b/modules/ingest-geoip/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/ingest/geoip/FullClusterRestartIT.java
@@ -17,7 +17,6 @@
 import org.elasticsearch.test.cluster.ElasticsearchCluster;
 import org.elasticsearch.test.cluster.FeatureFlag;
 import org.elasticsearch.test.cluster.local.distribution.DistributionType;
-import org.elasticsearch.test.cluster.util.Version;
 import org.elasticsearch.upgrades.FullClusterRestartUpgradeStatus;
 import org.elasticsearch.upgrades.ParameterizedFullClusterRestartTestCase;
 import org.junit.ClassRule;
@@ -41,7 +40,7 @@ public class FullClusterRestartIT extends ParameterizedFullClusterRestartTestCas
 
     private static final ElasticsearchCluster cluster = ElasticsearchCluster.local()
         .distribution(DistributionType.DEFAULT)
-        .version(Version.fromString(OLD_CLUSTER_VERSION))
+        .version(OLD_CLUSTER_VERSION, isOldClusterDetachedVersion())
         .nodes(2)
         .setting("ingest.geoip.downloader.endpoint", () -> fixture.getAddress(), s -> useFixture)
         .setting("xpack.security.enabled", "false")
diff --git a/qa/full-cluster-restart/build.gradle b/qa/full-cluster-restart/build.gradle
index 55881b7b29d20..26d51876b05ab 100644
--- a/qa/full-cluster-restart/build.gradle
+++ b/qa/full-cluster-restart/build.gradle
@@ -23,10 +23,20 @@ buildParams.bwcVersions.withIndexCompatible { bwcVersion, baseName ->
 }
 
 tasks.register("luceneBwcTest", StandaloneRestIntegTestTask) {
-  // We use a phony version here as the real version is provided via `tests.bwc.main.version` system property
-  usesBwcDistribution(Version.fromString("0.0.0"))
-  systemProperty("tests.old_cluster_version", "0.0.0")
-  onlyIf("tests.bwc.main.version system property exists") { System.getProperty("tests.bwc.main.version") != null }
+  project.gradle.taskGraph.whenReady { allTasks ->
+    if (allTasks.hasTask(getPath())) {
+      if (System.getProperty("tests.bwc.refspec.main") == null) {
+        throw new GradleException("You must set the `tests.bwc.refspec.main` system property to run luceneBwcTest")
+      }
+      if (System.getProperty("tests.bwc.main.version") == null) {
+        throw new GradleException("You must set the `tests.bwc.main.version` system property to run luceneBwcTest")
+      }
+    }
+  }
+  if (System.getProperty("tests.bwc.refspec.main") != null && System.getProperty("tests.bwc.main.version") != null) {
+    usesBwcDistributionFromRef(System.getProperty("tests.bwc.refspec.main"), Version.fromString(System.getProperty("tests.bwc.main.version")))
+    systemProperty("tests.old_cluster_version", System.getProperty("tests.bwc.main.version"))
+  }
 }
 
 tasks.named("bcUpgradeTest").configure {
diff --git a/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/upgrades/FullClusterRestartArchivedSettingsIT.java b/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/upgrades/FullClusterRestartArchivedSettingsIT.java
index fe0a9f33cb226..d1781afa9dbea 100644
--- a/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/upgrades/FullClusterRestartArchivedSettingsIT.java
+++ b/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/upgrades/FullClusterRestartArchivedSettingsIT.java
@@ -21,7 +21,6 @@
 import org.elasticsearch.test.cluster.FeatureFlag;
 import org.elasticsearch.test.cluster.local.LocalClusterConfigProvider;
 import org.elasticsearch.test.cluster.local.distribution.DistributionType;
-import org.elasticsearch.test.cluster.util.Version;
 import org.elasticsearch.test.rest.ObjectPath;
 import org.junit.ClassRule;
 import org.junit.rules.RuleChain;
@@ -45,7 +44,7 @@ public class FullClusterRestartArchivedSettingsIT extends ParameterizedFullClust
 
     private static ElasticsearchCluster cluster = ElasticsearchCluster.local()
         .distribution(DistributionType.DEFAULT)
-        .version(Version.fromString(OLD_CLUSTER_VERSION))
+        .version(OLD_CLUSTER_VERSION, isOldClusterDetachedVersion())
         .nodes(2)
         .setting("path.repo", () -> repoDirectory.getRoot().getPath())
         .setting("xpack.security.enabled", "false")
diff --git a/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/upgrades/FullClusterRestartDownsampleIT.java b/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/upgrades/FullClusterRestartDownsampleIT.java
index 71352355fb61e..10bbd3dc42e67 100644
--- a/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/upgrades/FullClusterRestartDownsampleIT.java
+++ b/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/upgrades/FullClusterRestartDownsampleIT.java
@@ -50,7 +50,7 @@ private static ElasticsearchCluster buildCluster() {
         Version oldVersion = Version.fromString(OLD_CLUSTER_VERSION);
         var cluster = ElasticsearchCluster.local()
             .distribution(DistributionType.DEFAULT)
-            .version(Version.fromString(OLD_CLUSTER_VERSION))
+            .version(OLD_CLUSTER_VERSION, isOldClusterDetachedVersion())
             .nodes(2)
             .setting("xpack.security.enabled", "false")
             .setting("indices.lifecycle.poll_interval", "5s")
diff --git a/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/upgrades/FullClusterRestartIT.java b/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/upgrades/FullClusterRestartIT.java
index cbe383a7da550..b0fda4051bf4b 100644
--- a/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/upgrades/FullClusterRestartIT.java
+++ b/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/upgrades/FullClusterRestartIT.java
@@ -109,7 +109,7 @@ private static ElasticsearchCluster buildCluster() {
         Version oldVersion = Version.fromString(OLD_CLUSTER_VERSION);
         var cluster = ElasticsearchCluster.local()
             .distribution(DistributionType.DEFAULT)
-            .version(Version.fromString(OLD_CLUSTER_VERSION))
+            .version(OLD_CLUSTER_VERSION, isOldClusterDetachedVersion())
             .nodes(2)
             .setting("path.repo", () -> repoDirectory.getRoot().getPath())
             .setting("xpack.security.enabled", "false")
diff --git a/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/upgrades/LogsIndexModeFullClusterRestartIT.java b/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/upgrades/LogsIndexModeFullClusterRestartIT.java
index d677c6adf2459..7236bcba96b3f 100644
--- a/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/upgrades/LogsIndexModeFullClusterRestartIT.java
+++ b/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/upgrades/LogsIndexModeFullClusterRestartIT.java
@@ -39,7 +39,7 @@ private static ElasticsearchCluster buildCluster() {
         Version oldVersion = Version.fromString(OLD_CLUSTER_VERSION);
         var cluster = ElasticsearchCluster.local()
             .distribution(DistributionType.DEFAULT)
-            .version(Version.fromString(OLD_CLUSTER_VERSION))
+            .version(OLD_CLUSTER_VERSION, isOldClusterDetachedVersion())
             .module("constant-keyword")
             .module("data-streams")
             .module("mapper-extras")
diff --git a/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/upgrades/QueryBuilderBWCIT.java b/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/upgrades/QueryBuilderBWCIT.java
index d336de92c3e93..701bf83e5e6eb 100644
--- a/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/upgrades/QueryBuilderBWCIT.java
+++ b/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/upgrades/QueryBuilderBWCIT.java
@@ -73,7 +73,7 @@ public class QueryBuilderBWCIT extends ParameterizedFullClusterRestartTestCase {
     @ClassRule
     public static ElasticsearchCluster cluster = ElasticsearchCluster.local()
         .distribution(DistributionType.DEFAULT)
-        .version(org.elasticsearch.test.cluster.util.Version.fromString(OLD_CLUSTER_VERSION))
+        .version(OLD_CLUSTER_VERSION, isOldClusterDetachedVersion())
         .nodes(2)
         .setting("xpack.security.enabled", "false")
         .apply(() -> clusterConfig)
diff --git a/qa/rolling-upgrade/src/javaRestTest/java/org/elasticsearch/upgrades/AbstractRollingUpgradeTestCase.java b/qa/rolling-upgrade/src/javaRestTest/java/org/elasticsearch/upgrades/AbstractRollingUpgradeTestCase.java
index 87096277cfce6..c702d82912aca 100644
--- a/qa/rolling-upgrade/src/javaRestTest/java/org/elasticsearch/upgrades/AbstractRollingUpgradeTestCase.java
+++ b/qa/rolling-upgrade/src/javaRestTest/java/org/elasticsearch/upgrades/AbstractRollingUpgradeTestCase.java
@@ -30,11 +30,9 @@ public abstract class AbstractRollingUpgradeTestCase extends ParameterizedRollin
     private static final ElasticsearchCluster cluster = buildCluster();
 
     private static ElasticsearchCluster buildCluster() {
-        // Note we need to use OLD_CLUSTER_VERSION directly here, as it may contain special values (e.g. 0.0.0) the ElasticsearchCluster
-        // builder uses to lookup a particular distribution
         var cluster = ElasticsearchCluster.local()
             .distribution(DistributionType.DEFAULT)
-            .version(OLD_CLUSTER_VERSION)
+            .version(getOldClusterVersion(), isOldClusterDetachedVersion())
             .nodes(NODE_NUM)
             .setting("path.repo", new Supplier<>() {
                 @Override
diff --git a/qa/rolling-upgrade/src/javaRestTest/java/org/elasticsearch/upgrades/AbstractRollingUpgradeWithSecurityTestCase.java b/qa/rolling-upgrade/src/javaRestTest/java/org/elasticsearch/upgrades/AbstractRollingUpgradeWithSecurityTestCase.java
index 961e4a353df95..accbef575e923 100644
--- a/qa/rolling-upgrade/src/javaRestTest/java/org/elasticsearch/upgrades/AbstractRollingUpgradeWithSecurityTestCase.java
+++ b/qa/rolling-upgrade/src/javaRestTest/java/org/elasticsearch/upgrades/AbstractRollingUpgradeWithSecurityTestCase.java
@@ -35,11 +35,9 @@ public abstract class AbstractRollingUpgradeWithSecurityTestCase extends Paramet
     private static final ElasticsearchCluster cluster = buildCluster();
 
     private static ElasticsearchCluster buildCluster() {
-        // Note we need to use OLD_CLUSTER_VERSION directly here, as it may contain special values (e.g. 0.0.0) the ElasticsearchCluster
-        // builder uses to lookup a particular distribution
         var cluster = ElasticsearchCluster.local()
             .distribution(DistributionType.DEFAULT)
-            .version(OLD_CLUSTER_VERSION)
+            .version(getOldClusterVersion(), isOldClusterDetachedVersion())
             .nodes(NODE_NUM)
             .user(USER, PASS)
             .setting("xpack.security.autoconfiguration.enabled", "false")
diff --git a/qa/rolling-upgrade/src/javaRestTest/java/org/elasticsearch/upgrades/FileSettingsUpgradeIT.java b/qa/rolling-upgrade/src/javaRestTest/java/org/elasticsearch/upgrades/FileSettingsUpgradeIT.java
index 6d16714cc67bb..9ac2d39ee2ef4 100644
--- a/qa/rolling-upgrade/src/javaRestTest/java/org/elasticsearch/upgrades/FileSettingsUpgradeIT.java
+++ b/qa/rolling-upgrade/src/javaRestTest/java/org/elasticsearch/upgrades/FileSettingsUpgradeIT.java
@@ -57,11 +57,9 @@ public class FileSettingsUpgradeIT extends ParameterizedRollingUpgradeTestCase {
 
     private static final TemporaryFolder repoDirectory = new TemporaryFolder();
 
-    // Note we need to use OLD_CLUSTER_VERSION directly here, as it may contain special values (e.g. 0.0.0) the ElasticsearchCluster
-    // builder uses to lookup a particular distribution
     private static final ElasticsearchCluster cluster = ElasticsearchCluster.local()
         .distribution(DistributionType.DEFAULT)
-        .version(OLD_CLUSTER_VERSION)
+        .version(getOldClusterVersion(), isOldClusterDetachedVersion())
         .nodes(NODE_NUM)
         .setting("path.repo", new Supplier<>() {
             @Override
diff --git a/qa/rolling-upgrade/src/javaRestTest/java/org/elasticsearch/upgrades/ParameterizedRollingUpgradeTestCase.java b/qa/rolling-upgrade/src/javaRestTest/java/org/elasticsearch/upgrades/ParameterizedRollingUpgradeTestCase.java
index 41a60a2880afb..af2beef5f6c8a 100644
--- a/qa/rolling-upgrade/src/javaRestTest/java/org/elasticsearch/upgrades/ParameterizedRollingUpgradeTestCase.java
+++ b/qa/rolling-upgrade/src/javaRestTest/java/org/elasticsearch/upgrades/ParameterizedRollingUpgradeTestCase.java
@@ -36,7 +36,7 @@
 
 public abstract class ParameterizedRollingUpgradeTestCase extends ESRestTestCase {
     protected static final int NODE_NUM = 3;
-    protected static final String OLD_CLUSTER_VERSION = System.getProperty("tests.old_cluster_version");
+    private static final String OLD_CLUSTER_VERSION = System.getProperty("tests.old_cluster_version");
     private static final Set<Integer> upgradedNodes = new HashSet<>();
     private static TestFeatureService oldClusterTestFeatureService = null;
     private static boolean upgradeFailed = false;
@@ -158,9 +158,8 @@ protected static String getOldClusterVersion() {
     }
 
     protected static boolean isOldClusterVersion(String nodeVersion, String buildHash) {
-        String bwcRefSpec = System.getProperty("tests.bwc.refspec.main");
-        if (bwcRefSpec != null) {
-            return bwcRefSpec.equals(buildHash);
+        if (isOldClusterDetachedVersion()) {
+            return System.getProperty("tests.bwc.refspec.main").equals(buildHash);
         }
         return getOldClusterVersion().equals(nodeVersion);
     }
diff --git a/test/framework/src/main/java/org/elasticsearch/test/rest/ESRestTestCase.java b/test/framework/src/main/java/org/elasticsearch/test/rest/ESRestTestCase.java
index 1572c82510202..db1f50b9a30b4 100644
--- a/test/framework/src/main/java/org/elasticsearch/test/rest/ESRestTestCase.java
+++ b/test/framework/src/main/java/org/elasticsearch/test/rest/ESRestTestCase.java
@@ -364,6 +364,14 @@ protected static boolean testFeatureServiceInitialized() {
         return testFeatureService != ALL_FEATURES;
     }
 
+    /**
+     * Whether the old cluster version is not of the released versions, but a detached build.
+     * In that case the Git ref has to be specified via {@code tests.bwc.refspec.main} system property.
+     */
+    protected static boolean isOldClusterDetachedVersion() {
+        return System.getProperty("tests.bwc.refspec.main") != null;
+    }
+
     @BeforeClass
     public static void initializeProjectIds() {
         // The active project-id is slightly longer, and has a fixed prefix so that it's easier to pick in error messages etc.
diff --git a/test/test-clusters/src/main/java/org/elasticsearch/test/cluster/local/AbstractLocalClusterFactory.java b/test/test-clusters/src/main/java/org/elasticsearch/test/cluster/local/AbstractLocalClusterFactory.java
index 0b3361065857d..1d52d305c18e3 100644
--- a/test/test-clusters/src/main/java/org/elasticsearch/test/cluster/local/AbstractLocalClusterFactory.java
+++ b/test/test-clusters/src/main/java/org/elasticsearch/test/cluster/local/AbstractLocalClusterFactory.java
@@ -923,7 +923,7 @@ private Map<String, String> getEnvironmentVariables() {
         }
 
         private boolean jdkIsIncompatible(Version version) {
-            return version.after("0.0.0") && version.before(FIRST_DISTRO_WITH_JDK_21);
+            return version.before(FIRST_DISTRO_WITH_JDK_21);
         }
 
         private record ReplacementKey(String key, String fallback) {
diff --git a/test/test-clusters/src/main/java/org/elasticsearch/test/cluster/local/AbstractLocalSpecBuilder.java b/test/test-clusters/src/main/java/org/elasticsearch/test/cluster/local/AbstractLocalSpecBuilder.java
index 3deadf49cca30..ea5c76bd551c8 100644
--- a/test/test-clusters/src/main/java/org/elasticsearch/test/cluster/local/AbstractLocalSpecBuilder.java
+++ b/test/test-clusters/src/main/java/org/elasticsearch/test/cluster/local/AbstractLocalSpecBuilder.java
@@ -305,6 +305,12 @@ public Version getVersion() {
         return inherit(() -> parent.getVersion(), version);
     }
 
+    @Override
+    public T version(String version, boolean detachedVersion) {
+        this.version = Version.fromString(version, detachedVersion);
+        return cast(this);
+    }
+
     private <T> List<T> inherit(Supplier<List<T>> parent, List<T> child) {
         List<T> combinedList = new ArrayList<>();
         if (this.parent != null) {
diff --git a/test/test-clusters/src/main/java/org/elasticsearch/test/cluster/local/LocalClusterSpec.java b/test/test-clusters/src/main/java/org/elasticsearch/test/cluster/local/LocalClusterSpec.java
index 633381cefbbbb..cccf2a95234c9 100644
--- a/test/test-clusters/src/main/java/org/elasticsearch/test/cluster/local/LocalClusterSpec.java
+++ b/test/test-clusters/src/main/java/org/elasticsearch/test/cluster/local/LocalClusterSpec.java
@@ -212,12 +212,7 @@ public Path getConfigDir() {
         }
 
         public boolean isSecurityEnabled() {
-            return Boolean.parseBoolean(
-                getSetting(
-                    "xpack.security.enabled",
-                    getVersion().equals(Version.fromString("0.0.0")) || getVersion().onOrAfter("8.0.0") ? "true" : "false"
-                )
-            );
+            return Boolean.parseBoolean(getSetting("xpack.security.enabled", getVersion().onOrAfter("8.0.0") ? "true" : "false"));
         }
 
         public boolean isRemoteClusterServerEnabled() {
diff --git a/test/test-clusters/src/main/java/org/elasticsearch/test/cluster/local/LocalSpecBuilder.java b/test/test-clusters/src/main/java/org/elasticsearch/test/cluster/local/LocalSpecBuilder.java
index 53d283224b26f..5be15687459e2 100644
--- a/test/test-clusters/src/main/java/org/elasticsearch/test/cluster/local/LocalSpecBuilder.java
+++ b/test/test-clusters/src/main/java/org/elasticsearch/test/cluster/local/LocalSpecBuilder.java
@@ -136,6 +136,16 @@ interface LocalSpecBuilder<T extends LocalSpecBuilder<?>> {
      */
     T version(String version);
 
+    /**
+     * Sets the version of Elasticsearch and whether it is a detached version.
+     * If not set, then defaults to {@link Version#CURRENT} and {@code false}.
+     *
+     * @param version the ES cluster version string
+     * @param detachedVersion true if using unreleased version of Elasticsearch that is also different from the local current HEAD.
+     *                        Defaults to false.
+     */
+    T version(String version, boolean detachedVersion);
+
     /**
      * Adds a system property to node JVM arguments.
      */
diff --git a/test/test-clusters/src/main/java/org/elasticsearch/test/cluster/local/distribution/LocalDistributionResolver.java b/test/test-clusters/src/main/java/org/elasticsearch/test/cluster/local/distribution/LocalDistributionResolver.java
index a853576d9b371..b42b5da249645 100644
--- a/test/test-clusters/src/main/java/org/elasticsearch/test/cluster/local/distribution/LocalDistributionResolver.java
+++ b/test/test-clusters/src/main/java/org/elasticsearch/test/cluster/local/distribution/LocalDistributionResolver.java
@@ -26,7 +26,7 @@ public LocalDistributionResolver(DistributionResolver delegate) {
 
     @Override
     public DistributionDescriptor resolve(Version version, DistributionType type) {
-        if (version.equals(Version.CURRENT)) {
+        if (version.equals(Version.CURRENT) && version.isDetached() == false) {
             String testDistributionPath = System.getProperty(type.getSystemProperty());
 
             if (testDistributionPath == null) {
diff --git a/test/test-clusters/src/main/java/org/elasticsearch/test/cluster/local/distribution/SnapshotDistributionResolver.java b/test/test-clusters/src/main/java/org/elasticsearch/test/cluster/local/distribution/SnapshotDistributionResolver.java
index db71f8cec9ab4..f57f36460b627 100644
--- a/test/test-clusters/src/main/java/org/elasticsearch/test/cluster/local/distribution/SnapshotDistributionResolver.java
+++ b/test/test-clusters/src/main/java/org/elasticsearch/test/cluster/local/distribution/SnapshotDistributionResolver.java
@@ -38,9 +38,8 @@ public DistributionDescriptor resolve(Version version, DistributionType type) {
             }
 
             // Snapshot distributions are never release builds and always use the default distribution
-            Version realVersion = Version.fromString(System.getProperty("tests.bwc.main.version", version.toString()));
             boolean isSnapshot = System.getProperty("tests.bwc.snapshot", "true").equals("false") == false;
-            return new DefaultDistributionDescriptor(realVersion, isSnapshot, distributionDir, DistributionType.DEFAULT);
+            return new DefaultDistributionDescriptor(version, isSnapshot, distributionDir, DistributionType.DEFAULT);
         }
 
         return delegate.resolve(version, type);
diff --git a/test/test-clusters/src/main/java/org/elasticsearch/test/cluster/util/Version.java b/test/test-clusters/src/main/java/org/elasticsearch/test/cluster/util/Version.java
index 2136d88a9e2aa..9115537c24204 100644
--- a/test/test-clusters/src/main/java/org/elasticsearch/test/cluster/util/Version.java
+++ b/test/test-clusters/src/main/java/org/elasticsearch/test/cluster/util/Version.java
@@ -33,6 +33,7 @@ public class Version implements Comparable<Version>, Serializable {
     private final int revision;
     private final int id;
     private final String qualifier;
+    private final boolean detached;
 
     static {
         Properties versionProperties = new Properties();
@@ -65,6 +66,10 @@ public Version(int major, int minor, int revision) {
     }
 
     public Version(int major, int minor, int revision, String qualifier) {
+        this(major, minor, revision, qualifier, false);
+    }
+
+    protected Version(int major, int minor, int revision, String qualifier, boolean detached) {
         this.major = major;
         this.minor = minor;
         this.revision = revision;
@@ -73,6 +78,7 @@ public Version(int major, int minor, int revision, String qualifier) {
         this.id = major * 10000000 + minor * 100000 + revision * 1000;
 
         this.qualifier = qualifier;
+        this.detached = detached;
     }
 
     public static Version fromString(final String s) {
@@ -80,6 +86,14 @@ public static Version fromString(final String s) {
     }
 
     public static Version fromString(final String s, final Mode mode) {
+        return fromString(s, mode, false);
+    }
+
+    public static Version fromString(final String s, final boolean detached) {
+        return fromString(s, Mode.STRICT, detached);
+    }
+
+    private static Version fromString(final String s, final Mode mode, final boolean detached) {
         Objects.requireNonNull(s);
         Matcher matcher = mode == Mode.STRICT ? pattern.matcher(s) : relaxedPattern.matcher(s);
         if (matcher.matches() == false) {
@@ -94,7 +108,13 @@ public static Version fromString(final String s, final Mode mode) {
         String revision = matcher.group(3);
         String qualifier = matcher.group(4);
 
-        return new Version(Integer.parseInt(major), Integer.parseInt(minor), revision == null ? 0 : Integer.parseInt(revision), qualifier);
+        return new Version(
+            Integer.parseInt(major),
+            Integer.parseInt(minor),
+            revision == null ? 0 : Integer.parseInt(revision),
+            qualifier,
+            detached
+        );
     }
 
     public static Optional<Version> tryParse(final String s) {
@@ -160,12 +180,12 @@ public boolean equals(Object o) {
             return false;
         }
         Version version = (Version) o;
-        return major == version.major && minor == version.minor && revision == version.revision;
+        return major == version.major && minor == version.minor && revision == version.revision && detached == version.detached;
     }
 
     @Override
     public int hashCode() {
-        return Objects.hash(major, minor, revision, id);
+        return Objects.hash(major, minor, revision, id, detached);
     }
 
     public int getMajor() {
@@ -188,6 +208,15 @@ public String getQualifier() {
         return qualifier;
     }
 
+    /**
+     * Informs if the version is not tied to any Elasticsearch release and is a custom build.
+     * This is true when the distribution is not from HEAD but also not any known released version.
+     * In that case the detached source build needs to be prepared by `usedBwcDistributionFromRef(ref, version)`.
+     */
+    public boolean isDetached() {
+        return detached;
+    }
+
     @Override
     public int compareTo(Version other) {
         return Integer.compare(getId(), other.getId());
diff --git a/x-pack/plugin/ent-search/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/xpack/application/FullClusterRestartIT.java b/x-pack/plugin/ent-search/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/xpack/application/FullClusterRestartIT.java
index 7bebd8fe05a54..a536998635d63 100644
--- a/x-pack/plugin/ent-search/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/xpack/application/FullClusterRestartIT.java
+++ b/x-pack/plugin/ent-search/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/xpack/application/FullClusterRestartIT.java
@@ -41,7 +41,7 @@ public class FullClusterRestartIT extends ParameterizedFullClusterRestartTestCas
     @ClassRule
     public static final ElasticsearchCluster cluster = ElasticsearchCluster.local()
         .distribution(DistributionType.DEFAULT)
-        .version(org.elasticsearch.test.cluster.util.Version.fromString(OLD_CLUSTER_VERSION))
+        .version(OLD_CLUSTER_VERSION, isOldClusterDetachedVersion())
         .nodes(2)
         .setting("xpack.security.enabled", "false")
         .setting("xpack.license.self_generated.type", "trial")
diff --git a/x-pack/plugin/esql/qa/server/mixed-cluster/src/javaRestTest/java/org/elasticsearch/xpack/esql/qa/mixed/Clusters.java b/x-pack/plugin/esql/qa/server/mixed-cluster/src/javaRestTest/java/org/elasticsearch/xpack/esql/qa/mixed/Clusters.java
index 9d4043dccab6a..c68561b3b3594 100644
--- a/x-pack/plugin/esql/qa/server/mixed-cluster/src/javaRestTest/java/org/elasticsearch/xpack/esql/qa/mixed/Clusters.java
+++ b/x-pack/plugin/esql/qa/server/mixed-cluster/src/javaRestTest/java/org/elasticsearch/xpack/esql/qa/mixed/Clusters.java
@@ -13,12 +13,14 @@
 
 public class Clusters {
     public static ElasticsearchCluster mixedVersionCluster() {
-        Version oldVersion = Version.fromString(System.getProperty("tests.old_cluster_version"));
+        String oldVersionString = System.getProperty("tests.old_cluster_version");
+        Version oldVersion = Version.fromString(oldVersionString);
+        boolean isDetachedVersion = System.getProperty("tests.bwc.refspec.main") != null;
         var cluster = ElasticsearchCluster.local()
             .distribution(DistributionType.DEFAULT)
-            .withNode(node -> node.version(oldVersion))
+            .withNode(node -> node.version(oldVersionString, isDetachedVersion))
             .withNode(node -> node.version(Version.CURRENT))
-            .withNode(node -> node.version(oldVersion))
+            .withNode(node -> node.version(oldVersionString, isDetachedVersion))
             .withNode(node -> node.version(Version.CURRENT))
             .setting("xpack.security.enabled", "false")
             .setting("xpack.license.self_generated.type", "trial");
diff --git a/x-pack/plugin/esql/qa/server/mixed-cluster/src/javaRestTest/java/org/elasticsearch/xpack/esql/qa/mixed/MixedClusterEsqlSpecIT.java b/x-pack/plugin/esql/qa/server/mixed-cluster/src/javaRestTest/java/org/elasticsearch/xpack/esql/qa/mixed/MixedClusterEsqlSpecIT.java
index 93e2ecb14c2ff..c35ba5b92b65b 100644
--- a/x-pack/plugin/esql/qa/server/mixed-cluster/src/javaRestTest/java/org/elasticsearch/xpack/esql/qa/mixed/MixedClusterEsqlSpecIT.java
+++ b/x-pack/plugin/esql/qa/server/mixed-cluster/src/javaRestTest/java/org/elasticsearch/xpack/esql/qa/mixed/MixedClusterEsqlSpecIT.java
@@ -32,7 +32,11 @@ protected String getTestRestCluster() {
         return cluster.getHttpAddresses();
     }
 
-    static final Version bwcVersion = Version.fromString(System.getProperty("tests.old_cluster_version"));
+    static final Version bwcVersion = Version.fromString(
+        System.getProperty("tests.old_cluster_version") != null
+            ? System.getProperty("tests.old_cluster_version").replace("-SNAPSHOT", "")
+            : null
+    );
 
     private static TestFeatureService oldClusterTestFeatureService = null;
 
diff --git a/x-pack/plugin/inference/qa/mixed-cluster/src/javaRestTest/java/org/elasticsearch/xpack/inference/qa/mixed/CohereServiceMixedIT.java b/x-pack/plugin/inference/qa/mixed-cluster/src/javaRestTest/java/org/elasticsearch/xpack/inference/qa/mixed/CohereServiceMixedIT.java
index c16271ed44083..961c36efac3b3 100644
--- a/x-pack/plugin/inference/qa/mixed-cluster/src/javaRestTest/java/org/elasticsearch/xpack/inference/qa/mixed/CohereServiceMixedIT.java
+++ b/x-pack/plugin/inference/qa/mixed-cluster/src/javaRestTest/java/org/elasticsearch/xpack/inference/qa/mixed/CohereServiceMixedIT.java
@@ -7,9 +7,9 @@
 
 package org.elasticsearch.xpack.inference.qa.mixed;
 
-import org.elasticsearch.Version;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.inference.TaskType;
+import org.elasticsearch.test.cluster.util.Version;
 import org.elasticsearch.test.http.MockResponse;
 import org.elasticsearch.test.http.MockWebServer;
 import org.elasticsearch.xpack.inference.services.cohere.embeddings.CohereEmbeddingType;
@@ -21,7 +21,6 @@
 import java.util.List;
 import java.util.Map;
 
-import static org.elasticsearch.xpack.inference.qa.mixed.MixedClusterSpecTestCase.bwcVersion;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.empty;
 import static org.hamcrest.Matchers.hasEntry;
diff --git a/x-pack/plugin/inference/qa/mixed-cluster/src/javaRestTest/java/org/elasticsearch/xpack/inference/qa/mixed/HuggingFaceServiceMixedIT.java b/x-pack/plugin/inference/qa/mixed-cluster/src/javaRestTest/java/org/elasticsearch/xpack/inference/qa/mixed/HuggingFaceServiceMixedIT.java
index 457ae525b7f4b..63cffb6fdee33 100644
--- a/x-pack/plugin/inference/qa/mixed-cluster/src/javaRestTest/java/org/elasticsearch/xpack/inference/qa/mixed/HuggingFaceServiceMixedIT.java
+++ b/x-pack/plugin/inference/qa/mixed-cluster/src/javaRestTest/java/org/elasticsearch/xpack/inference/qa/mixed/HuggingFaceServiceMixedIT.java
@@ -7,9 +7,9 @@
 
 package org.elasticsearch.xpack.inference.qa.mixed;
 
-import org.elasticsearch.Version;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.inference.TaskType;
+import org.elasticsearch.test.cluster.util.Version;
 import org.elasticsearch.test.http.MockResponse;
 import org.elasticsearch.test.http.MockWebServer;
 import org.junit.AfterClass;
diff --git a/x-pack/plugin/inference/qa/mixed-cluster/src/javaRestTest/java/org/elasticsearch/xpack/inference/qa/mixed/MixedClusterSpecTestCase.java b/x-pack/plugin/inference/qa/mixed-cluster/src/javaRestTest/java/org/elasticsearch/xpack/inference/qa/mixed/MixedClusterSpecTestCase.java
index 45cd3716f21df..172d52bd1a8db 100644
--- a/x-pack/plugin/inference/qa/mixed-cluster/src/javaRestTest/java/org/elasticsearch/xpack/inference/qa/mixed/MixedClusterSpecTestCase.java
+++ b/x-pack/plugin/inference/qa/mixed-cluster/src/javaRestTest/java/org/elasticsearch/xpack/inference/qa/mixed/MixedClusterSpecTestCase.java
@@ -7,9 +7,9 @@
 
 package org.elasticsearch.xpack.inference.qa.mixed;
 
-import org.elasticsearch.Version;
 import org.elasticsearch.features.NodeFeature;
 import org.elasticsearch.test.cluster.ElasticsearchCluster;
+import org.elasticsearch.test.cluster.util.Version;
 import org.elasticsearch.test.rest.ESRestTestCase;
 import org.elasticsearch.test.rest.TestFeatureService;
 import org.junit.AfterClass;
diff --git a/x-pack/plugin/inference/qa/mixed-cluster/src/javaRestTest/java/org/elasticsearch/xpack/inference/qa/mixed/MixedClustersSpec.java b/x-pack/plugin/inference/qa/mixed-cluster/src/javaRestTest/java/org/elasticsearch/xpack/inference/qa/mixed/MixedClustersSpec.java
index 7802c2e966e01..00203d4b1261d 100644
--- a/x-pack/plugin/inference/qa/mixed-cluster/src/javaRestTest/java/org/elasticsearch/xpack/inference/qa/mixed/MixedClustersSpec.java
+++ b/x-pack/plugin/inference/qa/mixed-cluster/src/javaRestTest/java/org/elasticsearch/xpack/inference/qa/mixed/MixedClustersSpec.java
@@ -13,10 +13,11 @@
 
 public class MixedClustersSpec {
     public static ElasticsearchCluster mixedVersionCluster() {
-        Version oldVersion = Version.fromString(System.getProperty("tests.old_cluster_version"));
+        String oldVersion = System.getProperty("tests.old_cluster_version");
+        boolean isDetachedVersion = System.getProperty("tests.bwc.refspec.main") != null;
         return ElasticsearchCluster.local()
             .distribution(DistributionType.DEFAULT)
-            .withNode(node -> node.version(oldVersion))
+            .withNode(node -> node.version(oldVersion, isDetachedVersion))
             .withNode(node -> node.version(Version.CURRENT))
             .setting("xpack.security.enabled", "false")
             .setting("xpack.license.self_generated.type", "trial")
diff --git a/x-pack/plugin/inference/qa/mixed-cluster/src/javaRestTest/java/org/elasticsearch/xpack/inference/qa/mixed/OpenAIServiceMixedIT.java b/x-pack/plugin/inference/qa/mixed-cluster/src/javaRestTest/java/org/elasticsearch/xpack/inference/qa/mixed/OpenAIServiceMixedIT.java
index b37bd1801b331..749684db43aac 100644
--- a/x-pack/plugin/inference/qa/mixed-cluster/src/javaRestTest/java/org/elasticsearch/xpack/inference/qa/mixed/OpenAIServiceMixedIT.java
+++ b/x-pack/plugin/inference/qa/mixed-cluster/src/javaRestTest/java/org/elasticsearch/xpack/inference/qa/mixed/OpenAIServiceMixedIT.java
@@ -7,9 +7,9 @@
 
 package org.elasticsearch.xpack.inference.qa.mixed;
 
-import org.elasticsearch.Version;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.inference.TaskType;
+import org.elasticsearch.test.cluster.util.Version;
 import org.elasticsearch.test.http.MockResponse;
 import org.elasticsearch.test.http.MockWebServer;
 import org.junit.AfterClass;
diff --git a/x-pack/plugin/inference/qa/rolling-upgrade/src/javaRestTest/java/org/elasticsearch/xpack/application/InferenceUpgradeTestCase.java b/x-pack/plugin/inference/qa/rolling-upgrade/src/javaRestTest/java/org/elasticsearch/xpack/application/InferenceUpgradeTestCase.java
index 7b28c562b13fc..7e80e8643d4cc 100644
--- a/x-pack/plugin/inference/qa/rolling-upgrade/src/javaRestTest/java/org/elasticsearch/xpack/application/InferenceUpgradeTestCase.java
+++ b/x-pack/plugin/inference/qa/rolling-upgrade/src/javaRestTest/java/org/elasticsearch/xpack/application/InferenceUpgradeTestCase.java
@@ -35,12 +35,10 @@ public InferenceUpgradeTestCase(@Name("upgradedNodes") int upgradedNodes) {
         super(upgradedNodes);
     }
 
-    // Note we need to use OLD_CLUSTER_VERSION directly here, as it may contain special values (e.g. 0.0.0) the ElasticsearchCluster
-    // builder uses to lookup a particular distribution
     @ClassRule
     public static ElasticsearchCluster cluster = ElasticsearchCluster.local()
         .distribution(DistributionType.DEFAULT)
-        .version(OLD_CLUSTER_VERSION)
+        .version(getOldClusterVersion(), isOldClusterDetachedVersion())
         .nodes(NODE_NUM)
         .setting("xpack.security.enabled", "false")
         .setting("xpack.license.self_generated.type", "trial")
diff --git a/x-pack/plugin/logsdb/qa/rolling-upgrade/src/javaRestTest/java/org/elasticsearch/upgrades/StandardToLogsDbIndexModeRollingUpgradeIT.java b/x-pack/plugin/logsdb/qa/rolling-upgrade/src/javaRestTest/java/org/elasticsearch/upgrades/StandardToLogsDbIndexModeRollingUpgradeIT.java
index e8cf3027ac067..bf969736e6c01 100644
--- a/x-pack/plugin/logsdb/qa/rolling-upgrade/src/javaRestTest/java/org/elasticsearch/upgrades/StandardToLogsDbIndexModeRollingUpgradeIT.java
+++ b/x-pack/plugin/logsdb/qa/rolling-upgrade/src/javaRestTest/java/org/elasticsearch/upgrades/StandardToLogsDbIndexModeRollingUpgradeIT.java
@@ -46,7 +46,7 @@ public class StandardToLogsDbIndexModeRollingUpgradeIT extends AbstractRollingUp
     @ClassRule()
     public static final ElasticsearchCluster cluster = ElasticsearchCluster.local()
         .distribution(DistributionType.DEFAULT)
-        .version(OLD_CLUSTER_VERSION)
+        .version(getOldClusterVersion(), isOldClusterDetachedVersion())
         .nodes(NODE_NUM)
         .user(USER, PASS)
         .module("constant-keyword")
diff --git a/x-pack/plugin/security/qa/multi-cluster/src/javaRestTest/java/org/elasticsearch/xpack/remotecluster/RemoteClusterSecurityBWCToRCS1ClusterRestIT.java b/x-pack/plugin/security/qa/multi-cluster/src/javaRestTest/java/org/elasticsearch/xpack/remotecluster/RemoteClusterSecurityBWCToRCS1ClusterRestIT.java
index 73e0f096039f9..2de7a4be792db 100644
--- a/x-pack/plugin/security/qa/multi-cluster/src/javaRestTest/java/org/elasticsearch/xpack/remotecluster/RemoteClusterSecurityBWCToRCS1ClusterRestIT.java
+++ b/x-pack/plugin/security/qa/multi-cluster/src/javaRestTest/java/org/elasticsearch/xpack/remotecluster/RemoteClusterSecurityBWCToRCS1ClusterRestIT.java
@@ -26,11 +26,11 @@
  */
 public class RemoteClusterSecurityBWCToRCS1ClusterRestIT extends AbstractRemoteClusterSecurityBWCRestIT {
 
-    private static final Version OLD_CLUSTER_VERSION = Version.fromString(System.getProperty("tests.old_cluster_version"));
+    private static final String OLD_CLUSTER_VERSION = System.getProperty("tests.old_cluster_version");
 
     static {
         fulfillingCluster = ElasticsearchCluster.local()
-            .version(OLD_CLUSTER_VERSION)
+            .version(OLD_CLUSTER_VERSION, isOldClusterDetachedVersion())
             .distribution(DistributionType.DEFAULT)
             .name("fulfilling-cluster")
             .apply(commonClusterConfig)
diff --git a/x-pack/plugin/security/qa/multi-cluster/src/javaRestTest/java/org/elasticsearch/xpack/remotecluster/RemoteClusterSecurityBWCToRCS2ClusterRestIT.java b/x-pack/plugin/security/qa/multi-cluster/src/javaRestTest/java/org/elasticsearch/xpack/remotecluster/RemoteClusterSecurityBWCToRCS2ClusterRestIT.java
index 5e173b72c66de..c53cca6054fce 100644
--- a/x-pack/plugin/security/qa/multi-cluster/src/javaRestTest/java/org/elasticsearch/xpack/remotecluster/RemoteClusterSecurityBWCToRCS2ClusterRestIT.java
+++ b/x-pack/plugin/security/qa/multi-cluster/src/javaRestTest/java/org/elasticsearch/xpack/remotecluster/RemoteClusterSecurityBWCToRCS2ClusterRestIT.java
@@ -9,7 +9,6 @@
 
 import org.elasticsearch.test.cluster.ElasticsearchCluster;
 import org.elasticsearch.test.cluster.local.distribution.DistributionType;
-import org.elasticsearch.test.cluster.util.Version;
 import org.junit.Before;
 import org.junit.ClassRule;
 import org.junit.rules.RuleChain;
@@ -27,14 +26,14 @@
  */
 public class RemoteClusterSecurityBWCToRCS2ClusterRestIT extends AbstractRemoteClusterSecurityBWCRestIT {
 
-    private static final Version OLD_CLUSTER_VERSION = Version.fromString(System.getProperty("tests.old_cluster_version"));
+    private static final String OLD_CLUSTER_VERSION = System.getProperty("tests.old_cluster_version");
     private static final AtomicReference<Map<String, Object>> API_KEY_MAP_REF = new AtomicReference<>();
 
     static {
 
         fulfillingCluster = ElasticsearchCluster.local()
             .name("fulfilling-cluster")
-            .version(OLD_CLUSTER_VERSION)
+            .version(OLD_CLUSTER_VERSION, isOldClusterDetachedVersion())
             .distribution(DistributionType.DEFAULT)
             .apply(commonClusterConfig)
             .setting("xpack.ml.enabled", "false")
diff --git a/x-pack/plugin/shutdown/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/xpack/restart/FullClusterRestartIT.java b/x-pack/plugin/shutdown/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/xpack/restart/FullClusterRestartIT.java
index d04560a2f47b2..3df11ac6661d7 100644
--- a/x-pack/plugin/shutdown/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/xpack/restart/FullClusterRestartIT.java
+++ b/x-pack/plugin/shutdown/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/xpack/restart/FullClusterRestartIT.java
@@ -17,7 +17,6 @@
 import org.elasticsearch.test.cluster.ElasticsearchCluster;
 import org.elasticsearch.test.cluster.FeatureFlag;
 import org.elasticsearch.test.cluster.local.distribution.DistributionType;
-import org.elasticsearch.test.cluster.util.Version;
 import org.elasticsearch.test.cluster.util.resource.Resource;
 import org.elasticsearch.test.rest.ESRestTestCase;
 import org.elasticsearch.upgrades.FullClusterRestartUpgradeStatus;
@@ -46,7 +45,7 @@ public class FullClusterRestartIT extends ParameterizedFullClusterRestartTestCas
     @ClassRule
     public static ElasticsearchCluster cluster = ElasticsearchCluster.local()
         .distribution(DistributionType.DEFAULT)
-        .version(Version.fromString(OLD_CLUSTER_VERSION))
+        .version(OLD_CLUSTER_VERSION, isOldClusterDetachedVersion())
         .nodes(2)
         // some tests rely on the translog not being flushed
         .setting("indices.memory.shard_inactive_time", "60m")
diff --git a/x-pack/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/xpack/restart/AbstractXpackFullClusterRestartTestCase.java b/x-pack/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/xpack/restart/AbstractXpackFullClusterRestartTestCase.java
index 2c3e2e1ee69a3..9b209da0033f7 100644
--- a/x-pack/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/xpack/restart/AbstractXpackFullClusterRestartTestCase.java
+++ b/x-pack/qa/full-cluster-restart/src/javaRestTest/java/org/elasticsearch/xpack/restart/AbstractXpackFullClusterRestartTestCase.java
@@ -10,7 +10,6 @@
 import org.elasticsearch.test.cluster.ElasticsearchCluster;
 import org.elasticsearch.test.cluster.FeatureFlag;
 import org.elasticsearch.test.cluster.local.distribution.DistributionType;
-import org.elasticsearch.test.cluster.util.Version;
 import org.elasticsearch.test.cluster.util.resource.Resource;
 import org.elasticsearch.upgrades.FullClusterRestartUpgradeStatus;
 import org.elasticsearch.upgrades.ParameterizedFullClusterRestartTestCase;
@@ -21,7 +20,7 @@ public abstract class AbstractXpackFullClusterRestartTestCase extends Parameteri
     @ClassRule
     public static ElasticsearchCluster cluster = ElasticsearchCluster.local()
         .distribution(DistributionType.DEFAULT)
-        .version(Version.fromString(OLD_CLUSTER_VERSION))
+        .version(OLD_CLUSTER_VERSION, isOldClusterDetachedVersion())
         .nodes(2)
         // some tests rely on the translog not being flushed
         .setting("indices.memory.shard_inactive_time", "60m")