diff --git a/temporal-sdk/src/main/java/io/temporal/internal/worker/ActivityWorker.java b/temporal-sdk/src/main/java/io/temporal/internal/worker/ActivityWorker.java
index 2a90c7780..3387ee760 100644
--- a/temporal-sdk/src/main/java/io/temporal/internal/worker/ActivityWorker.java
+++ b/temporal-sdk/src/main/java/io/temporal/internal/worker/ActivityWorker.java
@@ -26,6 +26,7 @@
 import java.util.Optional;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
 import javax.annotation.Nonnull;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -48,6 +49,7 @@ final class ActivityWorker implements SuspendableWorker {
   private final GrpcRetryer grpcRetryer;
   private final GrpcRetryer.GrpcRetryerOptions replyGrpcRetryerOptions;
   private final TrackingSlotSupplier<ActivitySlotInfo> slotSupplier;
+  private final AtomicBoolean serverSupportsAutoscaling;
 
   public ActivityWorker(
       @Nonnull WorkflowServiceStubs service,
@@ -56,7 +58,8 @@ public ActivityWorker(
       double taskQueueActivitiesPerSecond,
       @Nonnull SingleWorkerOptions options,
       @Nonnull ActivityTaskHandler handler,
-      @Nonnull SlotSupplier<ActivitySlotInfo> slotSupplier) {
+      @Nonnull SlotSupplier<ActivitySlotInfo> slotSupplier,
+      @Nonnull AtomicBoolean serverSupportsAutoscaling) {
     this.service = Objects.requireNonNull(service);
     this.namespace = Objects.requireNonNull(namespace);
     this.taskQueue = Objects.requireNonNull(taskQueue);
@@ -72,6 +75,7 @@ public ActivityWorker(
             DefaultStubServiceOperationRpcRetryOptions.INSTANCE, null);
 
     this.slotSupplier = new TrackingSlotSupplier<>(slotSupplier, this.workerMetricsScope);
+    this.serverSupportsAutoscaling = serverSupportsAutoscaling;
   }
 
   @Override
@@ -106,6 +110,7 @@ public boolean start() {
                     service.getServerCapabilities()),
                 this.pollTaskExecutor,
                 pollerOptions,
+                serverSupportsAutoscaling.get(),
                 workerMetricsScope);
 
       } else {
diff --git a/temporal-sdk/src/main/java/io/temporal/internal/worker/AsyncPoller.java b/temporal-sdk/src/main/java/io/temporal/internal/worker/AsyncPoller.java
index d7a62d3f5..510634379 100644
--- a/temporal-sdk/src/main/java/io/temporal/internal/worker/AsyncPoller.java
+++ b/temporal-sdk/src/main/java/io/temporal/internal/worker/AsyncPoller.java
@@ -29,6 +29,7 @@ final class AsyncPoller<T extends ScalingTask> extends BasePoller<T> {
   private final List<PollTaskAsync<T>> asyncTaskPollers;
   private final PollerOptions pollerOptions;
   private final PollerBehaviorAutoscaling pollerBehavior;
+  private final boolean serverSupportsAutoscaling;
   private final Scope workerMetricsScope;
   private Throttler pollRateThrottler;
   private final Thread.UncaughtExceptionHandler uncaughtExceptionHandler =
@@ -42,6 +43,7 @@ final class AsyncPoller<T extends ScalingTask> extends BasePoller<T> {
       PollTaskAsync<T> asyncTaskPoller,
       ShutdownableTaskExecutor<T> taskExecutor,
       PollerOptions pollerOptions,
+      boolean serverSupportsAutoscaling,
       Scope workerMetricsScope) {
     this(
         slotSupplier,
@@ -49,6 +51,7 @@ final class AsyncPoller<T extends ScalingTask> extends BasePoller<T> {
         Collections.singletonList(asyncTaskPoller),
         taskExecutor,
         pollerOptions,
+        serverSupportsAutoscaling,
         workerMetricsScope);
   }
 
@@ -58,6 +61,7 @@ final class AsyncPoller<T extends ScalingTask> extends BasePoller<T> {
       List<PollTaskAsync<T>> asyncTaskPollers,
       ShutdownableTaskExecutor<T> taskExecutor,
       PollerOptions pollerOptions,
+      boolean serverSupportsAutoscaling,
       Scope workerMetricsScope) {
     super(taskExecutor);
     Objects.requireNonNull(slotSupplier, "slotSupplier cannot be null");
@@ -78,6 +82,7 @@ final class AsyncPoller<T extends ScalingTask> extends BasePoller<T> {
               + " is not supported for AsyncPoller. Only PollerBehaviorAutoscaling is supported.");
     }
     this.pollerBehavior = (PollerBehaviorAutoscaling) pollerOptions.getPollerBehavior();
+    this.serverSupportsAutoscaling = serverSupportsAutoscaling;
     this.pollerOptions = pollerOptions;
     this.workerMetricsScope = workerMetricsScope;
   }
@@ -109,6 +114,7 @@ public boolean start() {
               pollerBehavior.getMinConcurrentTaskPollers(),
               pollerBehavior.getMaxConcurrentTaskPollers(),
               pollerBehavior.getInitialConcurrentTaskPollers(),
+              serverSupportsAutoscaling,
               (newTarget) -> {
                 log.debug(
                     "Updating maximum number of pollers for {} to: {}",
diff --git a/temporal-sdk/src/main/java/io/temporal/internal/worker/NexusWorker.java b/temporal-sdk/src/main/java/io/temporal/internal/worker/NexusWorker.java
index e179e12db..f5291cb16 100644
--- a/temporal-sdk/src/main/java/io/temporal/internal/worker/NexusWorker.java
+++ b/temporal-sdk/src/main/java/io/temporal/internal/worker/NexusWorker.java
@@ -30,6 +30,7 @@
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
+import java.util.concurrent.atomic.AtomicBoolean;
 import javax.annotation.Nonnull;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -52,6 +53,7 @@ final class NexusWorker implements SuspendableWorker {
   private final GrpcRetryer grpcRetryer;
   private final GrpcRetryer.GrpcRetryerOptions replyGrpcRetryerOptions;
   private final TrackingSlotSupplier<NexusSlotInfo> slotSupplier;
+  private final AtomicBoolean serverSupportsAutoscaling;
   private final boolean forceOldFailureFormat;
 
   public NexusWorker(
@@ -61,7 +63,8 @@ public NexusWorker(
       @Nonnull SingleWorkerOptions options,
       @Nonnull NexusTaskHandler handler,
       @Nonnull DataConverter dataConverter,
-      @Nonnull SlotSupplier<NexusSlotInfo> slotSupplier) {
+      @Nonnull SlotSupplier<NexusSlotInfo> slotSupplier,
+      @Nonnull AtomicBoolean serverSupportsAutoscaling) {
     this.service = Objects.requireNonNull(service);
     this.namespace = Objects.requireNonNull(namespace);
     this.taskQueue = Objects.requireNonNull(taskQueue);
@@ -77,6 +80,7 @@ public NexusWorker(
             DefaultStubServiceOperationRpcRetryOptions.INSTANCE, null);
 
     this.slotSupplier = new TrackingSlotSupplier<>(slotSupplier, this.workerMetricsScope);
+    this.serverSupportsAutoscaling = serverSupportsAutoscaling;
     // Allow tests to force old format for backward compatibility testing
     String forceOldFormat = System.getProperty("temporal.nexus.forceOldFailureFormat");
     this.forceOldFailureFormat = "true".equalsIgnoreCase(forceOldFormat);
@@ -112,6 +116,7 @@ public boolean start() {
                     this.slotSupplier),
                 this.pollTaskExecutor,
                 pollerOptions,
+                serverSupportsAutoscaling.get(),
                 workerMetricsScope);
       } else {
         poller =
@@ -282,6 +287,7 @@ public Throwable wrapFailure(NexusTask task, Throwable failure) {
           "Failure processing nexus response: " + response.getRequest().toString(), failure);
     }
 
+    @SuppressWarnings("deprecation") // Uses deprecated operationError
     private void handleNexusTask(NexusTask task, Scope metricsScope) {
       PollNexusTaskQueueResponseOrBuilder pollResponse = task.getResponse();
       ByteString taskToken = pollResponse.getTaskToken();
@@ -374,6 +380,7 @@ private void logExceptionDuringResultReporting(
       }
     }
 
+    @SuppressWarnings("deprecation") // Uses deprecated setOperationError
     private Response getResponseForOldServer(Response response) {
       Response.Builder b = response.toBuilder();
       Failure failure = response.getStartOperation().getFailure();
diff --git a/temporal-sdk/src/main/java/io/temporal/internal/worker/PollScaleReportHandle.java b/temporal-sdk/src/main/java/io/temporal/internal/worker/PollScaleReportHandle.java
index 925c60e0b..d56ab9d89 100644
--- a/temporal-sdk/src/main/java/io/temporal/internal/worker/PollScaleReportHandle.java
+++ b/temporal-sdk/src/main/java/io/temporal/internal/worker/PollScaleReportHandle.java
@@ -18,6 +18,7 @@ public class PollScaleReportHandle<T extends ScalingTask> implements Runnable {
   private final int maxPollerCount;
   private int targetPollerCount;
   private final Functions.Proc1<Integer> scaleCallback;
+  private final boolean serverSupportsAutoscaling;
   private boolean everSawScalingDecision;
   private int ingestedThisPeriod;
   private int ingestedLastPeriod;
@@ -27,18 +28,20 @@ public PollScaleReportHandle(
       int minPollerCount,
       int maxPollerCount,
       int initialPollerCount,
+      boolean serverSupportsAutoscaling,
       Functions.Proc1<Integer> scaleCallback) {
     this.minPollerCount = minPollerCount;
     this.maxPollerCount = maxPollerCount;
     this.targetPollerCount = initialPollerCount;
+    this.serverSupportsAutoscaling = serverSupportsAutoscaling;
     this.scaleCallback = scaleCallback;
   }
 
   public synchronized void report(T task, Throwable e) {
     if (e != null) {
       // We want to avoid scaling down on errors if we have never seen a scaling decision
-      // since we might never scale up again.
-      if (!everSawScalingDecision) {
+      // and the server doesn't support autoscaling - otherwise we might never scale up again.
+      if (!everSawScalingDecision && !serverSupportsAutoscaling) {
         return;
       }
       if ((e instanceof StatusRuntimeException)) {
@@ -68,9 +71,10 @@ public synchronized void report(T task, Throwable e) {
         updateTarget((t -> t + deltaSuggestion));
       }
 
-    } else if (task == null && everSawScalingDecision) {
+    } else if (task == null && (everSawScalingDecision || serverSupportsAutoscaling)) {
       // We want to avoid scaling down on empty polls if the server has never made any
-      // scaling decisions - otherwise we might never scale up again.
+      // scaling decisions and doesn't support autoscaling - otherwise we might never scale
+      // up again.
       updateTarget((t) -> t - 1);
     }
   }
diff --git a/temporal-sdk/src/main/java/io/temporal/internal/worker/SyncActivityWorker.java b/temporal-sdk/src/main/java/io/temporal/internal/worker/SyncActivityWorker.java
index 55ff1a32c..87ddc7c4a 100644
--- a/temporal-sdk/src/main/java/io/temporal/internal/worker/SyncActivityWorker.java
+++ b/temporal-sdk/src/main/java/io/temporal/internal/worker/SyncActivityWorker.java
@@ -11,6 +11,8 @@
 import java.util.concurrent.Executors;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+import javax.annotation.Nonnull;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -32,7 +34,8 @@ public SyncActivityWorker(
       String taskQueue,
       double taskQueueActivitiesPerSecond,
       SingleWorkerOptions options,
-      SlotSupplier<ActivitySlotInfo> slotSupplier) {
+      SlotSupplier<ActivitySlotInfo> slotSupplier,
+      @Nonnull AtomicBoolean serverSupportsAutoscaling) {
     this.identity = options.getIdentity();
     this.namespace = namespace;
     this.taskQueue = taskQueue;
@@ -72,7 +75,8 @@ public SyncActivityWorker(
             taskQueueActivitiesPerSecond,
             options,
             taskHandler,
-            slotSupplier);
+            slotSupplier,
+            serverSupportsAutoscaling);
   }
 
   public void registerActivityImplementations(Object... activitiesImplementation) {
diff --git a/temporal-sdk/src/main/java/io/temporal/internal/worker/SyncNexusWorker.java b/temporal-sdk/src/main/java/io/temporal/internal/worker/SyncNexusWorker.java
index bc089644d..23471f86e 100644
--- a/temporal-sdk/src/main/java/io/temporal/internal/worker/SyncNexusWorker.java
+++ b/temporal-sdk/src/main/java/io/temporal/internal/worker/SyncNexusWorker.java
@@ -6,6 +6,8 @@
 import io.temporal.worker.tuning.SlotSupplier;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+import javax.annotation.Nonnull;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -23,7 +25,8 @@ public SyncNexusWorker(
       String namespace,
       String taskQueue,
       SingleWorkerOptions options,
-      SlotSupplier<NexusSlotInfo> slotSupplier) {
+      SlotSupplier<NexusSlotInfo> slotSupplier,
+      @Nonnull AtomicBoolean serverSupportsAutoscaling) {
     this.identity = options.getIdentity();
     this.namespace = namespace;
     this.taskQueue = taskQueue;
@@ -43,7 +46,8 @@ public SyncNexusWorker(
             options,
             taskHandler,
             options.getDataConverter(),
-            slotSupplier);
+            slotSupplier,
+            serverSupportsAutoscaling);
   }
 
   @Override
diff --git a/temporal-sdk/src/main/java/io/temporal/internal/worker/SyncWorkflowWorker.java b/temporal-sdk/src/main/java/io/temporal/internal/worker/SyncWorkflowWorker.java
index 37c977572..2b94effb6 100644
--- a/temporal-sdk/src/main/java/io/temporal/internal/worker/SyncWorkflowWorker.java
+++ b/temporal-sdk/src/main/java/io/temporal/internal/worker/SyncWorkflowWorker.java
@@ -25,6 +25,7 @@
 import java.util.Objects;
 import java.util.Optional;
 import java.util.concurrent.*;
+import java.util.concurrent.atomic.AtomicBoolean;
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 import org.slf4j.Logger;
@@ -68,7 +69,8 @@ public SyncWorkflowWorker(
       @Nonnull WorkflowThreadExecutor workflowThreadExecutor,
       @Nonnull EagerActivityDispatcher eagerActivityDispatcher,
       @Nonnull SlotSupplier<WorkflowSlotInfo> slotSupplier,
-      @Nonnull SlotSupplier<LocalActivitySlotInfo> laSlotSupplier) {
+      @Nonnull SlotSupplier<LocalActivitySlotInfo> laSlotSupplier,
+      @Nonnull AtomicBoolean serverSupportsAutoscaling) {
     this.identity = singleWorkerOptions.getIdentity();
     this.namespace = namespace;
     this.taskQueue = taskQueue;
@@ -122,7 +124,8 @@ public SyncWorkflowWorker(
             cache,
             taskHandler,
             eagerActivityDispatcher,
-            slotSupplier);
+            slotSupplier,
+            serverSupportsAutoscaling);
 
     // Exists to support Worker#replayWorkflowExecution functionality.
     // This handler has to be non-sticky to avoid evicting actual executions from the cache
diff --git a/temporal-sdk/src/main/java/io/temporal/internal/worker/WorkflowWorker.java b/temporal-sdk/src/main/java/io/temporal/internal/worker/WorkflowWorker.java
index 2193acf59..4986808c4 100644
--- a/temporal-sdk/src/main/java/io/temporal/internal/worker/WorkflowWorker.java
+++ b/temporal-sdk/src/main/java/io/temporal/internal/worker/WorkflowWorker.java
@@ -30,6 +30,7 @@
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.RejectedExecutionException;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 import org.slf4j.Logger;
@@ -54,6 +55,7 @@ final class WorkflowWorker implements SuspendableWorker {
   private final GrpcRetryer grpcRetryer;
   private final EagerActivityDispatcher eagerActivityDispatcher;
   private final TrackingSlotSupplier<WorkflowSlotInfo> slotSupplier;
+  private final AtomicBoolean serverSupportsAutoscaling;
 
   private PollTaskExecutor<WorkflowTask> pollTaskExecutor;
 
@@ -73,7 +75,8 @@ public WorkflowWorker(
       @Nonnull WorkflowExecutorCache cache,
       @Nonnull WorkflowTaskHandler handler,
       @Nonnull EagerActivityDispatcher eagerActivityDispatcher,
-      @Nonnull SlotSupplier<WorkflowSlotInfo> slotSupplier) {
+      @Nonnull SlotSupplier<WorkflowSlotInfo> slotSupplier,
+      @Nonnull AtomicBoolean serverSupportsAutoscaling) {
     this.service = Objects.requireNonNull(service);
     this.namespace = Objects.requireNonNull(namespace);
     this.taskQueue = Objects.requireNonNull(taskQueue);
@@ -88,6 +91,7 @@ public WorkflowWorker(
     this.grpcRetryer = new GrpcRetryer(service.getServerCapabilities());
     this.eagerActivityDispatcher = eagerActivityDispatcher;
     this.slotSupplier = new TrackingSlotSupplier<>(slotSupplier, this.workerMetricsScope);
+    this.serverSupportsAutoscaling = serverSupportsAutoscaling;
   }
 
   @Override
@@ -154,6 +158,7 @@ public boolean start() {
                 pollers,
                 this.pollTaskExecutor,
                 pollerOptions,
+                serverSupportsAutoscaling.get(),
                 workerMetricsScope);
       } else {
         PollerBehaviorSimpleMaximum pollerBehavior =
diff --git a/temporal-sdk/src/main/java/io/temporal/worker/Worker.java b/temporal-sdk/src/main/java/io/temporal/worker/Worker.java
index ed761558b..5ffd300e9 100644
--- a/temporal-sdk/src/main/java/io/temporal/worker/Worker.java
+++ b/temporal-sdk/src/main/java/io/temporal/worker/Worker.java
@@ -69,7 +69,8 @@ public final class Worker {
       boolean useStickyTaskQueue,
       WorkflowThreadExecutor workflowThreadExecutor,
       List<ContextPropagator> contextPropagators,
-      @Nonnull List<WorkerPlugin> plugins) {
+      @Nonnull List<WorkerPlugin> plugins,
+      @Nonnull AtomicBoolean serverSupportsAutoscaling) {
 
     Objects.requireNonNull(client, "client should not be null");
     this.plugins = Objects.requireNonNull(plugins, "plugins should not be null");
@@ -102,7 +103,8 @@ public final class Worker {
               taskQueue,
               this.options.getMaxTaskQueueActivitiesPerSecond(),
               activityOptions,
-              activitySlotSupplier);
+              activitySlotSupplier,
+              serverSupportsAutoscaling);
     }
 
     EagerActivityDispatcher eagerActivityDispatcher =
@@ -120,7 +122,13 @@ public final class Worker {
     attachMetricsToResourceController(taggedScope, nexusSlotSupplier);
 
     nexusWorker =
-        new SyncNexusWorker(client, namespace, taskQueue, nexusOptions, nexusSlotSupplier);
+        new SyncNexusWorker(
+            client,
+            namespace,
+            taskQueue,
+            nexusOptions,
+            nexusSlotSupplier,
+            serverSupportsAutoscaling);
 
     SingleWorkerOptions singleWorkerOptions =
         toWorkflowWorkerOptions(
@@ -158,7 +166,8 @@ public final class Worker {
             workflowThreadExecutor,
             eagerActivityDispatcher,
             workflowSlotSupplier,
-            localActivitySlotSupplier);
+            localActivitySlotSupplier,
+            serverSupportsAutoscaling);
   }
 
   /**
diff --git a/temporal-sdk/src/main/java/io/temporal/worker/WorkerFactory.java b/temporal-sdk/src/main/java/io/temporal/worker/WorkerFactory.java
index 16f7305b7..3a22b7351 100644
--- a/temporal-sdk/src/main/java/io/temporal/worker/WorkerFactory.java
+++ b/temporal-sdk/src/main/java/io/temporal/worker/WorkerFactory.java
@@ -5,6 +5,7 @@
 import com.google.common.base.Strings;
 import com.uber.m3.tally.Scope;
 import io.temporal.api.workflowservice.v1.DescribeNamespaceRequest;
+import io.temporal.api.workflowservice.v1.DescribeNamespaceResponse;
 import io.temporal.client.WorkflowClient;
 import io.temporal.client.WorkflowClientOptions;
 import io.temporal.common.converter.DataConverter;
@@ -28,6 +29,7 @@
 import java.util.concurrent.SynchronousQueue;
 import java.util.concurrent.ThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.function.BiConsumer;
 import java.util.function.Consumer;
@@ -56,6 +58,9 @@ public final class WorkerFactory {
   /** Plugins propagated from the client and applied to this factory. */
   private final List<WorkerPlugin> plugins;
 
+  /** Set during start() if the namespace has the poller_autoscaling capability. */
+  private final AtomicBoolean pollerAutoscaling = new AtomicBoolean(false);
+
   private State state = State.Initial;
 
   private final String statusErrorMessage =
@@ -192,7 +197,8 @@ public synchronized Worker newWorker(String taskQueue, WorkerOptions options) {
               true,
               workflowThreadExecutor,
               workflowClient.getOptions().getContextPropagators(),
-              plugins);
+              plugins,
+              pollerAutoscaling);
       workers.put(taskQueue, worker);
 
       // Go through the plugins to call plugin initializeWorker hooks (e.g. register workflows,
@@ -251,13 +257,17 @@ public synchronized void start() {
 
     // Workers check and require that Temporal Server is available during start to fail-fast in case
     // of configuration issues.
-    workflowClient
-        .getWorkflowServiceStubs()
-        .blockingStub()
-        .describeNamespace(
-            DescribeNamespaceRequest.newBuilder()
-                .setNamespace(workflowClient.getOptions().getNamespace())
-                .build());
+    DescribeNamespaceResponse describeNamespaceResponse =
+        workflowClient
+            .getWorkflowServiceStubs()
+            .blockingStub()
+            .describeNamespace(
+                DescribeNamespaceRequest.newBuilder()
+                    .setNamespace(workflowClient.getOptions().getNamespace())
+                    .build());
+    if (describeNamespaceResponse.getNamespaceInfo().getCapabilities().getPollerAutoscaling()) {
+      pollerAutoscaling.set(true);
+    }
 
     // Build plugin execution chain (reverse order for proper nesting)
     Consumer<WorkerFactory> startChain = WorkerFactory::doStart;
diff --git a/temporal-sdk/src/test/java/io/temporal/internal/worker/AsyncPollerTest.java b/temporal-sdk/src/test/java/io/temporal/internal/worker/AsyncPollerTest.java
index e0c2443b5..2ade97762 100644
--- a/temporal-sdk/src/test/java/io/temporal/internal/worker/AsyncPollerTest.java
+++ b/temporal-sdk/src/test/java/io/temporal/internal/worker/AsyncPollerTest.java
@@ -133,6 +133,7 @@ private AsyncPoller<TestScalingTask> newPoller(
         pollTask,
         taskExecutor,
         options,
+        false,
         new NoopScope());
   }
 
diff --git a/temporal-sdk/src/test/java/io/temporal/internal/worker/PollScaleReportHandleTest.java b/temporal-sdk/src/test/java/io/temporal/internal/worker/PollScaleReportHandleTest.java
index 7edc3f69f..745818ae6 100644
--- a/temporal-sdk/src/test/java/io/temporal/internal/worker/PollScaleReportHandleTest.java
+++ b/temporal-sdk/src/test/java/io/temporal/internal/worker/PollScaleReportHandleTest.java
@@ -17,7 +17,7 @@ public void handleResourceExhaustedError() {
     Mockito.when(mockTask.getScalingDecision()).thenReturn(mockDecision);
     Mockito.when(mockDecision.getPollRequestDeltaSuggestion()).thenReturn(0);
     PollScaleReportHandle<ScalingTask> handle =
-        new PollScaleReportHandle<>(1, 10, 8, mockScaleCallback);
+        new PollScaleReportHandle<>(1, 10, 8, false, mockScaleCallback);
 
     // Simulate RESOURCE_EXHAUSTED error
     StatusRuntimeException exception = new StatusRuntimeException(Status.RESOURCE_EXHAUSTED);
@@ -37,7 +37,7 @@ public void handleGenericError() {
     Mockito.when(mockTask.getScalingDecision()).thenReturn(mockDecision);
     Mockito.when(mockDecision.getPollRequestDeltaSuggestion()).thenReturn(0);
     PollScaleReportHandle<ScalingTask> handle =
-        new PollScaleReportHandle<>(1, 10, 5, mockScaleCallback);
+        new PollScaleReportHandle<>(1, 10, 5, false, mockScaleCallback);
 
     // Simulate a generic error
     handle.report(mockTask, null);
@@ -57,7 +57,7 @@ public void applyScalingDecisionDeltaWhenAllowed() {
     Mockito.when(mockDecision.getPollRequestDeltaSuggestion()).thenReturn(3);
 
     PollScaleReportHandle<ScalingTask> handle =
-        new PollScaleReportHandle<>(1, 10, 5, mockScaleCallback);
+        new PollScaleReportHandle<>(1, 10, 5, false, mockScaleCallback);
     handle.run(); // Enable scale-up
 
     // Report a task with a scaling decision
@@ -66,4 +66,71 @@ public void applyScalingDecisionDeltaWhenAllowed() {
     // Verify target poller count is updated and callback is invoked
     Mockito.verify(mockScaleCallback).apply(8);
   }
+
+  @Test
+  public void scaleDownOnEmptyPollWhenServerSupportsAutoscaling() {
+    Functions.Proc1<Integer> mockScaleCallback = Mockito.mock(Functions.Proc1.class);
+    PollScaleReportHandle<ScalingTask> handle =
+        new PollScaleReportHandle<>(1, 10, 5, true, mockScaleCallback);
+
+    // Empty poll (null task, no error) should scale down when server supports autoscaling,
+    // even without having seen a scaling decision.
+    handle.report(null, null);
+
+    Mockito.verify(mockScaleCallback).apply(4);
+  }
+
+  @Test
+  public void noScaleDownOnEmptyPollWithoutAutoscalingOrDecision() {
+    Functions.Proc1<Integer> mockScaleCallback = Mockito.mock(Functions.Proc1.class);
+    PollScaleReportHandle<ScalingTask> handle =
+        new PollScaleReportHandle<>(1, 10, 5, false, mockScaleCallback);
+
+    // Empty poll should NOT scale down when server doesn't support autoscaling
+    // and we haven't seen a scaling decision.
+    handle.report(null, null);
+
+    Mockito.verifyNoInteractions(mockScaleCallback);
+  }
+
+  @Test
+  public void scaleDownOnErrorWhenServerSupportsAutoscaling() {
+    Functions.Proc1<Integer> mockScaleCallback = Mockito.mock(Functions.Proc1.class);
+    PollScaleReportHandle<ScalingTask> handle =
+        new PollScaleReportHandle<>(1, 10, 5, true, mockScaleCallback);
+
+    // Error should scale down when server supports autoscaling,
+    // even without a prior scaling decision.
+    handle.report(null, new RuntimeException("error"));
+
+    Mockito.verify(mockScaleCallback).apply(4);
+  }
+
+  @Test
+  public void noScaleDownOnErrorWithoutAutoscalingOrDecision() {
+    Functions.Proc1<Integer> mockScaleCallback = Mockito.mock(Functions.Proc1.class);
+    PollScaleReportHandle<ScalingTask> handle =
+        new PollScaleReportHandle<>(1, 10, 5, false, mockScaleCallback);
+
+    // Error should NOT scale down without autoscaling support or prior scaling decision.
+    handle.report(null, new RuntimeException("error"));
+
+    Mockito.verifyNoInteractions(mockScaleCallback);
+  }
+
+  @Test
+  public void scaleDownOnEmptyPollRespectsMinPollerCount() {
+    Functions.Proc1<Integer> mockScaleCallback = Mockito.mock(Functions.Proc1.class);
+    // min=3, initial=3, so scale down should be clamped
+    PollScaleReportHandle<ScalingTask> handle =
+        new PollScaleReportHandle<>(3, 10, 3, true, mockScaleCallback);
+
+    // Empty polls should not scale below minimum
+    for (int i = 0; i < 5; i++) {
+      handle.report(null, null);
+    }
+
+    // Should never have been called since target can't go below min
+    Mockito.verifyNoInteractions(mockScaleCallback);
+  }
 }
diff --git a/temporal-sdk/src/test/java/io/temporal/internal/worker/WorkflowWorkerTest.java b/temporal-sdk/src/test/java/io/temporal/internal/worker/WorkflowWorkerTest.java
index 7888f6cf8..cbe194091 100644
--- a/temporal-sdk/src/test/java/io/temporal/internal/worker/WorkflowWorkerTest.java
+++ b/temporal-sdk/src/test/java/io/temporal/internal/worker/WorkflowWorkerTest.java
@@ -31,6 +31,7 @@
 import java.time.Duration;
 import java.util.UUID;
 import java.util.concurrent.*;
+import java.util.concurrent.atomic.AtomicBoolean;
 import org.junit.Test;
 import org.mockito.stubbing.Answer;
 import org.slf4j.Logger;
@@ -83,7 +84,8 @@ public void concurrentPollRequestLockTest() throws Exception {
             cache,
             taskHandler,
             eagerActivityDispatcher,
-            slotSupplier);
+            slotSupplier,
+            new AtomicBoolean(false));
 
     WorkflowServiceGrpc.WorkflowServiceFutureStub futureStub =
         mock(WorkflowServiceGrpc.WorkflowServiceFutureStub.class);
@@ -252,7 +254,8 @@ public void respondWorkflowTaskFailureMetricTest() throws Exception {
             cache,
             taskHandler,
             eagerActivityDispatcher,
-            slotSupplier);
+            slotSupplier,
+            new AtomicBoolean(false));
 
     WorkflowServiceGrpc.WorkflowServiceFutureStub futureStub =
         mock(WorkflowServiceGrpc.WorkflowServiceFutureStub.class);
@@ -394,7 +397,8 @@ public boolean isAnyTypeSupported() {
             cache,
             taskHandler,
             eagerActivityDispatcher,
-            slotSupplier);
+            slotSupplier,
+            new AtomicBoolean(false));
 
     WorkflowServiceGrpc.WorkflowServiceBlockingStub blockingStub =
         mock(WorkflowServiceGrpc.WorkflowServiceBlockingStub.class);
diff --git a/temporal-serviceclient/src/main/proto b/temporal-serviceclient/src/main/proto
index 188e309de..db5f59306 160000
--- a/temporal-serviceclient/src/main/proto
+++ b/temporal-serviceclient/src/main/proto
@@ -1 +1 @@
-Subproject commit 188e309dee0acb3e3c84363d2d9f11be32df3bb8
+Subproject commit db5f593060ee579460e7f4e06d79b5e4f3af2387
diff --git a/temporal-test-server/src/main/java/io/temporal/internal/testservice/TestWorkflowService.java b/temporal-test-server/src/main/java/io/temporal/internal/testservice/TestWorkflowService.java
index 7183ade76..e73e6e7a8 100644
--- a/temporal-test-server/src/main/java/io/temporal/internal/testservice/TestWorkflowService.java
+++ b/temporal-test-server/src/main/java/io/temporal/internal/testservice/TestWorkflowService.java
@@ -1024,6 +1024,7 @@ private static Failure wrapNexusOperationFailure(Failure cause) {
   }
 
   @Override
+  @SuppressWarnings("deprecation") // Uses deprecated operationError
   public void respondNexusTaskCompleted(
       RespondNexusTaskCompletedRequest request,
       StreamObserver<RespondNexusTaskCompletedResponse> responseObserver) {
diff --git a/temporal-test-server/src/test/java/io/temporal/testserver/functional/NexusWorkflowTest.java b/temporal-test-server/src/test/java/io/temporal/testserver/functional/NexusWorkflowTest.java
index 26b269199..7db34c346 100644
--- a/temporal-test-server/src/test/java/io/temporal/testserver/functional/NexusWorkflowTest.java
+++ b/temporal-test-server/src/test/java/io/temporal/testserver/functional/NexusWorkflowTest.java
@@ -846,6 +846,7 @@ public void testNexusOperationStartToCloseTimeout() {
     }
   }
 
+  @SuppressWarnings("deprecation") // Uses deprecated operationError
   @Test
   public void testNexusOperationError() {
     Response unsuccessfulResp =
@@ -1159,6 +1160,7 @@ public void testNexusOperationCancelRequestAcknowledgeSchedulesWorkflowTask() {
   }
 
   @Test(timeout = 30000)
+  @SuppressWarnings("deprecation") // Uses deprecated operationError
   public void testNexusOperationCanceledErrorWithCauseChain() {
     // Verifies that a canceled OperationError with a JSON-encoded failure chain properly
     // unwraps the CanceledFailureInfo and preserves the cause.