diff --git a/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/inference/TrainedModelConfig.java b/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/inference/TrainedModelConfig.java
index 7ff7bb9b68ea8..b469d35b90383 100644
--- a/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/inference/TrainedModelConfig.java
+++ b/x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/inference/TrainedModelConfig.java
@@ -298,7 +298,7 @@ public TrainedModelConfig(StreamInput in) throws IOException {
         } else {
             platformArchitecture = null;
         }
-        if (in.getTransportVersion().onOrAfter(TransportVersions.ML_PACKAGE_LOADER_PLATFORM_ADDED)) {
+        if (in.getTransportVersion().onOrAfter(TransportVersions.ML_TRAINED_MODEL_PREFIX_STRINGS_ADDED)) {
             prefixStrings = in.readOptionalWriteable(TrainedModelPrefixStrings::new);
         }
     }
@@ -486,7 +486,7 @@ public void writeTo(StreamOutput out) throws IOException {
             out.writeOptionalString(platformArchitecture);
         }
 
-        if (out.getTransportVersion().onOrAfter(TransportVersions.ML_PACKAGE_LOADER_PLATFORM_ADDED)) {
+        if (out.getTransportVersion().onOrAfter(TransportVersions.ML_TRAINED_MODEL_PREFIX_STRINGS_ADDED)) {
             out.writeOptionalWriteable(prefixStrings);
         }
     }
diff --git a/x-pack/plugin/core/src/test/java/org/elasticsearch/xpack/core/ml/inference/TrainedModelConfigTests.java b/x-pack/plugin/core/src/test/java/org/elasticsearch/xpack/core/ml/inference/TrainedModelConfigTests.java
index 632b3fb60708a..5622914c2981c 100644
--- a/x-pack/plugin/core/src/test/java/org/elasticsearch/xpack/core/ml/inference/TrainedModelConfigTests.java
+++ b/x-pack/plugin/core/src/test/java/org/elasticsearch/xpack/core/ml/inference/TrainedModelConfigTests.java
@@ -463,6 +463,9 @@ protected TrainedModelConfig mutateInstanceForVersion(TrainedModelConfig instanc
         if (version.before(TransportVersions.ML_TRAINED_MODEL_CONFIG_PLATFORM_ADDED)) {
             builder.setPlatformArchitecture(null);
         }
+        if (version.before(TransportVersions.ML_TRAINED_MODEL_PREFIX_STRINGS_ADDED)) {
+            builder.setPrefixStrings(null);
+        }
         return builder.build();
     }
 }