diff --git a/lib/sdk/server/Makefile b/lib/sdk/server/Makefile
index 9dad9be..262ca5b 100644
--- a/lib/sdk/server/Makefile
+++ b/lib/sdk/server/Makefile
@@ -32,8 +32,8 @@ run-contract-tests:
 	@curl -s https://raw.githubusercontent.com/launchdarkly/sdk-test-harness/v2/downloader/run.sh \
       | VERSION=v2 PARAMS="-url http://localhost:$(TEST_SERVICE_PORT) -debug -skip-from=$(SUPPRESSION_FILE) $(TEST_HARNESS_PARAMS)" sh
 	@echo "Running SDK contract test v3.0.0-alpha.1..."
-	@curl -s https://raw.githubusercontent.com/launchdarkly/sdk-test-harness/v3.0.0-alpha.1/downloader/run.sh \
-      | VERSION=v3.0.0-alpha.1 PARAMS="-url http://localhost:$(TEST_SERVICE_PORT) -debug -stop-service-at-end -skip-from=$(SUPPRESSION_FILE_FDV2) $(TEST_HARNESS_PARAMS)" sh
+	@curl -s https://raw.githubusercontent.com/launchdarkly/sdk-test-harness/v3.0.0-alpha.3/downloader/run.sh \
+      | VERSION=v3.0.0-alpha.3 PARAMS="-url http://localhost:$(TEST_SERVICE_PORT) -debug -stop-service-at-end -skip-from=$(SUPPRESSION_FILE_FDV2) $(TEST_HARNESS_PARAMS)" sh
 
 contract-tests: build-contract-tests start-contract-test-service-bg run-contract-tests
 
diff --git a/lib/sdk/server/contract-tests/service/src/main/java/sdktest/Representations.java b/lib/sdk/server/contract-tests/service/src/main/java/sdktest/Representations.java
index 265150a..99890e7 100644
--- a/lib/sdk/server/contract-tests/service/src/main/java/sdktest/Representations.java
+++ b/lib/sdk/server/contract-tests/service/src/main/java/sdktest/Representations.java
@@ -133,7 +133,8 @@ public static class SdkConfigDataSystemParams {
     SdkConfigDataStoreParams store;
     Integer storeMode;
     SdkConfigDataInitializerParams[] initializers;
-    SdkConfigSynchronizersParams synchronizers;
+    /** List of synchronizers (matches servicedef DataSystem.Synchronizers). */
+    SdkConfigSynchronizerParams[] synchronizers;
     String payloadFilter;
   }
 
@@ -161,11 +162,6 @@ public static class SdkConfigDataInitializerParams {
     SdkConfigPollingParams polling;
   }
 
-  public static class SdkConfigSynchronizersParams {
-    SdkConfigSynchronizerParams primary;
-    SdkConfigSynchronizerParams secondary;
-  }
-
   public static class SdkConfigSynchronizerParams {
     SdkConfigStreamingParams streaming;
     SdkConfigPollingParams polling;
diff --git a/lib/sdk/server/contract-tests/service/src/main/java/sdktest/SdkClientEntity.java b/lib/sdk/server/contract-tests/service/src/main/java/sdktest/SdkClientEntity.java
index 22180a5..ced6e3f 100644
--- a/lib/sdk/server/contract-tests/service/src/main/java/sdktest/SdkClientEntity.java
+++ b/lib/sdk/server/contract-tests/service/src/main/java/sdktest/SdkClientEntity.java
@@ -70,7 +70,6 @@
 import sdktest.Representations.SdkConfigParams;
 import sdktest.Representations.SdkConfigDataSystemParams;
 import sdktest.Representations.SdkConfigDataInitializerParams;
-import sdktest.Representations.SdkConfigSynchronizersParams;
 import sdktest.Representations.SdkConfigSynchronizerParams;
 import sdktest.Representations.SdkConfigPollingParams;
 import sdktest.Representations.SdkConfigStreamingParams;
@@ -542,34 +541,23 @@ private LDConfig buildSdkConfig(SdkConfigParams params, String tag) {
         }
       }
 
-      // Configure synchronizers
-      if (params.dataSystem.synchronizers != null) {
-        List<DataSourceBuilder<Synchronizer>> synchronizers = new ArrayList<>();
 
-        // Primary synchronizer
-        if (params.dataSystem.synchronizers.primary != null) {
-          DataSourceBuilder<Synchronizer> primary = createSynchronizer(params.dataSystem.synchronizers.primary, params.dataSystem.payloadFilter);
-          if (primary != null) {
-            synchronizers.add(primary);
+      if (params.dataSystem.synchronizers != null && params.dataSystem.synchronizers.length > 0) {
+        List<DataSourceBuilder<Synchronizer>> synchronizerBuilders = new ArrayList<>();
+        for (SdkConfigSynchronizerParams syncParams : params.dataSystem.synchronizers) {
+          DataSourceBuilder<Synchronizer> sync = createSynchronizer(syncParams, params.dataSystem.payloadFilter);
+          if (sync != null) {
+            synchronizerBuilders.add(sync);
           }
         }
-
-        // Secondary synchronizer (optional)
-        if (params.dataSystem.synchronizers.secondary != null) {
-          DataSourceBuilder<Synchronizer> secondary = createSynchronizer(params.dataSystem.synchronizers.secondary, params.dataSystem.payloadFilter);
-          if (secondary != null) {
-            synchronizers.add(secondary);
-          }
-        }
-
-        if (!synchronizers.isEmpty()) {
-          dataSystemBuilder.synchronizers(synchronizers.toArray(new DataSourceBuilder[0]));
+        if (!synchronizerBuilders.isEmpty()) {
+          dataSystemBuilder.synchronizers(synchronizerBuilders.toArray(new DataSourceBuilder[0]));
         }
       }
 
-      // Configure FDv1 fallback synchronizer
+      // Configure FDv1 fallback synchronizer (pick first polling, else first synchronizer)
       SdkConfigSynchronizerParams fallbackSynchronizer =
-          selectFallbackSynchronizer(params.dataSystem);
+          selectFallbackSynchronizer(params.dataSystem.synchronizers);
       if (fallbackSynchronizer != null) {
         // Set global polling endpoints if the fallback synchronizer has polling with custom base URI
         if (fallbackSynchronizer.polling != null &&
@@ -624,32 +612,21 @@ private DataSourceBuilder<Synchronizer> createSynchronizer(
 
   /**
    * Selects the best synchronizer configuration to use for FDv1 fallback.
-   * Prefers polling synchronizers, falls back to primary synchronizer.
+   * Prefers the first polling synchronizer in the list, otherwise the first synchronizer.
    */
   private static SdkConfigSynchronizerParams selectFallbackSynchronizer(
-      SdkConfigDataSystemParams dataSystemParams) {
-
-    // Prefer secondary polling synchronizer
-    if (dataSystemParams.synchronizers != null &&
-        dataSystemParams.synchronizers.secondary != null &&
-        dataSystemParams.synchronizers.secondary.polling != null) {
-      return dataSystemParams.synchronizers.secondary;
-    }
-
-    // Fall back to primary polling synchronizer
-    if (dataSystemParams.synchronizers != null &&
-        dataSystemParams.synchronizers.primary != null &&
-        dataSystemParams.synchronizers.primary.polling != null) {
-      return dataSystemParams.synchronizers.primary;
+      SdkConfigSynchronizerParams[] synchronizers) {
+    if (synchronizers == null || synchronizers.length == 0) {
+      return null;
     }
-
-    // Fall back to primary synchronizer (even if streaming)
-    if (dataSystemParams.synchronizers != null &&
-        dataSystemParams.synchronizers.primary != null) {
-      return dataSystemParams.synchronizers.primary;
+    // Prefer first polling synchronizer (FDv1 fallback is polling-based)
+    for (SdkConfigSynchronizerParams sync : synchronizers) {
+      if (sync.polling != null) {
+        return sync;
+      }
     }
-
-    return null;
+    // Otherwise use first synchronizer (streaming; FDv1 will use default polling config)
+    return synchronizers[0];
   }
 
   /**