diff --git a/foundation-models/sap-rpt/src/main/java/com/sap/ai/sdk/foundationmodels/rpt/RptClient.java b/foundation-models/sap-rpt/src/main/java/com/sap/ai/sdk/foundationmodels/rpt/RptClient.java
index e968aff49..8bca6da74 100644
--- a/foundation-models/sap-rpt/src/main/java/com/sap/ai/sdk/foundationmodels/rpt/RptClient.java
+++ b/foundation-models/sap-rpt/src/main/java/com/sap/ai/sdk/foundationmodels/rpt/RptClient.java
@@ -9,12 +9,15 @@
 import com.sap.ai.sdk.core.JacksonConfiguration;
 import com.sap.ai.sdk.foundationmodels.rpt.generated.client.DefaultApi;
 import com.sap.ai.sdk.foundationmodels.rpt.generated.model.PredictRequestPayload;
+import com.sap.ai.sdk.foundationmodels.rpt.generated.model.PredictRequestPayloadOneOf;
+import com.sap.ai.sdk.foundationmodels.rpt.generated.model.PredictRequestPayloadOneOf1;
 import com.sap.ai.sdk.foundationmodels.rpt.generated.model.PredictResponsePayload;
 import com.sap.ai.sdk.foundationmodels.rpt.generated.model.PredictionConfig;
 import com.sap.cloud.sdk.cloudplatform.connectivity.Destination;
 import com.sap.cloud.sdk.services.openapi.apache.apiclient.ApiClient;
 import java.io.File;
 import java.util.Map;
+import java.util.Set;
 import javax.annotation.Nonnull;
 import lombok.AccessLevel;
 import lombok.RequiredArgsConstructor;
@@ -28,6 +31,15 @@
 public class RptClient {
   @Nonnull private final DefaultApi api;
   @Nonnull private final DefaultApi apiWithGzipEncoding;
+  private final boolean usesOldModel;
+
+  private static final Set<String> PRE1_6MODELS =
+      Set.of(
+          "sap-rpt-1-large",
+          "sap-rpt-1-small",
+          "sap-rpt-1.1-preview",
+          "sap-rpt-1.5",
+          "sap-rpt-1.5-large");
 
   /**
    * Creates a new RptClient for the specified foundation model.
@@ -39,8 +51,9 @@ public class RptClient {
   @Nonnull
   public static RptClient forModel(@Nonnull final RptModel foundationModel)
       throws DeploymentResolutionException {
+    final var usesOldModel = PRE1_6MODELS.contains(foundationModel.name());
     final var destination = new AiCoreService().getInferenceDestination().forModel(foundationModel);
-    return forDestination(destination);
+    return forDestination(destination, usesOldModel);
   }
 
   /**
@@ -49,10 +62,12 @@ public static RptClient forModel(@Nonnull final RptModel foundationModel)
    * @param destination The destination to use.
    * @return A new instance of RptClient.
    */
-  static RptClient forDestination(@Nonnull final Destination destination) {
+  static RptClient forDestination(
+      @Nonnull final Destination destination, final boolean usesOldModel) {
     final var apiClient = ApiClient.create(destination).withObjectMapper(getDefaultObjectMapper());
     final var api = new DefaultApi(apiClient);
-    return new RptClient(api, api.withDefaultHeaders(Map.of("Content-Encoding", "gzip")));
+    return new RptClient(
+        api, api.withDefaultHeaders(Map.of("Content-Encoding", "gzip")), usesOldModel);
   }
 
   /**
@@ -73,13 +88,31 @@ static RptClient forDestination(@Nonnull final Destination destination) {
    *
    * @param requestBody The prediction request
    * @return prediction response from the RPT model
+   * @apiNote When used with a pre-1.6 model, the {@code contextMode} field of the embedded {@link
+   *     com.sap.ai.sdk.foundationmodels.rpt.generated.model.PredictionConfig} is set to {@code
+   *     null} on the passed-in object as a side effect.
    */
   @Beta
   @Nonnull
   public PredictResponsePayload tableCompletion(@Nonnull final PredictRequestPayload requestBody) {
+    // contextMode has to be null for models < 1.6
+    if (usesOldModel) {
+      configFrom(requestBody).setContextMode(null);
+    }
     return apiWithGzipEncoding.predict(requestBody);
   }
 
+  @Nonnull
+  private static PredictionConfig configFrom(@Nonnull final PredictRequestPayload requestBody) {
+    if (requestBody instanceof PredictRequestPayloadOneOf rb) {
+      return rb.getPredictionConfig();
+    } else if (requestBody instanceof PredictRequestPayloadOneOf1 rb1) {
+      return rb1.getPredictionConfig();
+    }
+    throw new IllegalArgumentException(
+        "Unsupported PredictRequestPayload type: " + requestBody.getClass().getName());
+  }
+
   /**
    * Make in-context predictions for specified target columns based on provided table data Parquet
    * file.
@@ -100,12 +133,19 @@ public PredictResponsePayload tableCompletion(@Nonnull final PredictRequestPaylo
    * @param parquetFile Parquet file
    * @param predictionConfig The prediction configuration
    * @return prediction response from the RPT model
+   * @apiNote When used with a pre-1.6 model, the {@code contextMode} field of the passed-in {@link
+   *     com.sap.ai.sdk.foundationmodels.rpt.generated.model.PredictionConfig} is set to {@code
+   *     null} as a side effect.
    * @since 1.16.0
    */
   @Beta
   @Nonnull
   public PredictResponsePayload tableCompletion(
       @Nonnull final File parquetFile, @Nonnull final PredictionConfig predictionConfig) {
+    // contextMode has to be null for models < 1.6
+    if (usesOldModel) {
+      predictionConfig.setContextMode(null);
+    }
     try {
       final var config =
           JacksonConfiguration.getDefaultObjectMapper().writeValueAsString(predictionConfig);
diff --git a/foundation-models/sap-rpt/src/test/java/com/sap/ai/sdk/foundationmodels/rpt/RptClientTest.java b/foundation-models/sap-rpt/src/test/java/com/sap/ai/sdk/foundationmodels/rpt/RptClientTest.java
index 0047144c2..4f0dc7be0 100644
--- a/foundation-models/sap-rpt/src/test/java/com/sap/ai/sdk/foundationmodels/rpt/RptClientTest.java
+++ b/foundation-models/sap-rpt/src/test/java/com/sap/ai/sdk/foundationmodels/rpt/RptClientTest.java
@@ -1,5 +1,9 @@
 package com.sap.ai.sdk.foundationmodels.rpt;
 
+import static com.github.tomakehurst.wiremock.client.WireMock.aResponse;
+import static com.github.tomakehurst.wiremock.client.WireMock.post;
+import static com.github.tomakehurst.wiremock.client.WireMock.stubFor;
+import static com.github.tomakehurst.wiremock.client.WireMock.urlEqualTo;
 import static com.sap.ai.sdk.foundationmodels.rpt.generated.model.ColumnType.STRING;
 import static com.sap.ai.sdk.foundationmodels.rpt.generated.model.TargetColumnConfig.TaskTypeEnum.CLASSIFICATION;
 import static org.assertj.core.api.Assertions.assertThat;
@@ -60,7 +64,7 @@ class RptClientTest {
   void setup(final WireMockRuntimeInfo server) {
     final DefaultHttpDestination destination =
         DefaultHttpDestination.builder(server.getHttpBaseUrl()).build();
-    client = RptClient.forDestination(destination);
+    client = RptClient.forDestination(destination, false);
     ApacheHttpClient5Accessor.setHttpClientCache(ApacheHttpClient5Cache.DISABLED);
   }
 
@@ -302,4 +306,83 @@ void testTableCompletionWithParquetThrowsIllegalArgumentException() {
           .hasMessageContaining("Failed to serialize PredictionConfig");
     }
   }
+
+  @Test
+  void testOldModelThrowsOnUnknownPayloadType() {
+    final var oldModelClient =
+        RptClient.forDestination(DefaultHttpDestination.builder("http://localhost").build(), true);
+    final var unknownPayload = mock(PredictRequestPayload.class);
+
+    assertThatThrownBy(() -> oldModelClient.tableCompletion(unknownPayload))
+        .isInstanceOf(IllegalArgumentException.class)
+        .hasMessageContaining("Unsupported PredictRequestPayload type");
+  }
+
+  @Test
+  void testOldModelStripsContextModeFromRowWiseRequest(final WireMockRuntimeInfo server) {
+    stubFor(post(urlEqualTo("/predict")).willReturn(aResponse().withStatus(200).withBody("{}")));
+    final var oldModelClient =
+        RptClient.forDestination(
+            DefaultHttpDestination.builder(server.getHttpBaseUrl()).build(), true);
+
+    val config =
+        PredictionConfig.create()
+            .targetColumns(TARGET_COLUMN)
+            .contextMode(PredictionConfig.ContextModeEnum.DEEP);
+    val request =
+        PredictRequestPayloadOneOf.create()
+            .predictionConfig(config)
+            .rows(List.of())
+            .indexColumn("ID")
+            .dataSchema(DATA_SCHEMA)
+            .parseDataTypes(true);
+
+    assertThat(config.getContextMode()).isEqualTo(PredictionConfig.ContextModeEnum.DEEP);
+    oldModelClient.tableCompletion(request);
+    assertThat(config.getContextMode()).isNull();
+  }
+
+  @Test
+  void testOldModelStripsContextModeFromColumnWiseRequest(final WireMockRuntimeInfo server) {
+    stubFor(post(urlEqualTo("/predict")).willReturn(aResponse().withStatus(200).withBody("{}")));
+    final var oldModelClient =
+        RptClient.forDestination(
+            DefaultHttpDestination.builder(server.getHttpBaseUrl()).build(), true);
+
+    val config =
+        PredictionConfig.create()
+            .targetColumns(TARGET_COLUMN)
+            .contextMode(PredictionConfig.ContextModeEnum.DEFAULT);
+    val request =
+        PredictRequestPayloadOneOf1.create()
+            .predictionConfig(config)
+            .columns(Map.of())
+            .indexColumn("ID")
+            .dataSchema(DATA_SCHEMA)
+            .parseDataTypes(true);
+
+    assertThat(config.getContextMode()).isEqualTo(PredictionConfig.ContextModeEnum.DEFAULT);
+    oldModelClient.tableCompletion(request);
+    assertThat(config.getContextMode()).isNull();
+  }
+
+  @Test
+  void testOldModelStripsContextModeFromParquetRequest(final WireMockRuntimeInfo server) {
+    stubFor(
+        post(urlEqualTo("/predict_parquet"))
+            .willReturn(aResponse().withStatus(200).withBody("{}")));
+    final var oldModelClient =
+        RptClient.forDestination(
+            DefaultHttpDestination.builder(server.getHttpBaseUrl()).build(), true);
+
+    val parquetFile = Path.of("src/test/resources/rpt/test-data.parquet").toFile();
+    val predictionConfig =
+        PredictionConfig.create()
+            .targetColumns(TARGET_COLUMN)
+            .contextMode(PredictionConfig.ContextModeEnum.DEEP);
+
+    assertThat(predictionConfig.getContextMode()).isEqualTo(PredictionConfig.ContextModeEnum.DEEP);
+    oldModelClient.tableCompletion(parquetFile, predictionConfig);
+    assertThat(predictionConfig.getContextMode()).isNull();
+  }
 }