diff --git a/leshan-lwm2m-server/src/main/java/org/eclipse/leshan/server/registration/DefaultRegistrationDataExtractor.java b/leshan-lwm2m-server/src/main/java/org/eclipse/leshan/server/registration/DefaultRegistrationDataExtractor.java
index 2687e97e97..8e19c4aa8c 100644
--- a/leshan-lwm2m-server/src/main/java/org/eclipse/leshan/server/registration/DefaultRegistrationDataExtractor.java
+++ b/leshan-lwm2m-server/src/main/java/org/eclipse/leshan/server/registration/DefaultRegistrationDataExtractor.java
@@ -39,6 +39,10 @@ public class DefaultRegistrationDataExtractor implements RegistrationDataExtract
 
     @Override
     public RegistrationData extractDataFromObjectLinks(Link[] objectLinks, LwM2mVersion lwM2mVersion) {
+        if (!lwM2mVersion.isSupported()) {
+            return null;
+        }
+
         RegistrationData data = new RegistrationData();
         if (objectLinks != null) {
 
diff --git a/leshan-lwm2m-server/src/main/java/org/eclipse/leshan/server/registration/RegistrationDataExtractor.java b/leshan-lwm2m-server/src/main/java/org/eclipse/leshan/server/registration/RegistrationDataExtractor.java
index 2b11cfb67e..6361ef92c5 100644
--- a/leshan-lwm2m-server/src/main/java/org/eclipse/leshan/server/registration/RegistrationDataExtractor.java
+++ b/leshan-lwm2m-server/src/main/java/org/eclipse/leshan/server/registration/RegistrationDataExtractor.java
@@ -29,6 +29,9 @@
  */
 public interface RegistrationDataExtractor {
 
+    /**
+     * @return extracted {@link RegistrationData} or <code>null</code> if {@link LwM2mVersion} is not supported
+     */
     RegistrationData extractDataFromObjectLinks(Link[] objectLinks, LwM2mVersion lwM2mVersion);
 
     public class RegistrationData {
diff --git a/leshan-lwm2m-server/src/main/java/org/eclipse/leshan/server/registration/RegistrationHandler.java b/leshan-lwm2m-server/src/main/java/org/eclipse/leshan/server/registration/RegistrationHandler.java
index 74bfa1da52..d62cda7413 100644
--- a/leshan-lwm2m-server/src/main/java/org/eclipse/leshan/server/registration/RegistrationHandler.java
+++ b/leshan-lwm2m-server/src/main/java/org/eclipse/leshan/server/registration/RegistrationHandler.java
@@ -77,6 +77,9 @@ public SendableResponse<RegisterResponse> register(LwM2mPeer sender, RegisterReq
         LwM2mVersion lwM2mVersion = LwM2mVersion.get(registerRequest.getLwVersion());
         RegistrationData objLinksData = dataExtractor.extractDataFromObjectLinks(registerRequest.getObjectLinks(),
                 lwM2mVersion);
+        if (objLinksData == null) {
+            return new SendableResponse<>(RegisterResponse.preconditionFailed("unsupported lwm2m version"));
+        }
 
         // Create Registration from RegisterRequest
         Registration.Builder builder = new Registration.Builder(
diff --git a/leshan-lwm2m-server/src/test/java/org/eclipse/leshan/server/registration/RegistrationHandlerTest.java b/leshan-lwm2m-server/src/test/java/org/eclipse/leshan/server/registration/RegistrationHandlerTest.java
index 93734bbde8..59863c4d62 100644
--- a/leshan-lwm2m-server/src/test/java/org/eclipse/leshan/server/registration/RegistrationHandlerTest.java
+++ b/leshan-lwm2m-server/src/test/java/org/eclipse/leshan/server/registration/RegistrationHandlerTest.java
@@ -16,6 +16,7 @@
 package org.eclipse.leshan.server.registration;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
 
 import java.net.InetSocketAddress;
 import java.net.UnknownHostException;
@@ -23,6 +24,8 @@
 import java.util.HashMap;
 import java.util.Map;
 
+import org.eclipse.leshan.core.LwM2m.LwM2mVersion;
+import org.eclipse.leshan.core.ResponseCode;
 import org.eclipse.leshan.core.endpoint.EndpointUri;
 import org.eclipse.leshan.core.link.DefaultLinkParser;
 import org.eclipse.leshan.core.link.LinkParseException;
@@ -32,6 +35,8 @@
 import org.eclipse.leshan.core.request.RegisterRequest;
 import org.eclipse.leshan.core.request.UpdateRequest;
 import org.eclipse.leshan.core.request.UplinkRequest;
+import org.eclipse.leshan.core.response.RegisterResponse;
+import org.eclipse.leshan.core.response.SendableResponse;
 import org.eclipse.leshan.server.security.Authorizer;
 import org.eclipse.leshan.servers.DefaultServerEndpointNameProvider;
 import org.eclipse.leshan.servers.security.Authorization;
@@ -114,6 +119,18 @@ public void test_update_without_application_data_from_authorizer() {
         assertEquals(appData, registration.getApplicationData());
     }
 
+    @Test
+    public void test_unsupported_lwm2m_version() {
+        // handle REGISTER request
+        SendableResponse<RegisterResponse> response = registrationHandler.register(givenIdentity(),
+                givenRegisterRequestWithEndpoint("myEndpoint", LwM2mVersion.get("1.2")), givenServerEndpointUri());
+        assertEquals(response.getResponse().getCode(), ResponseCode.PRECONDITION_FAILED);
+
+        // check result
+        Registration registration = registrationStore.getRegistrationByEndpoint("myEndpoint");
+        assertNull(registration);
+    }
+
     private IpPeer givenIdentity() {
         return new IpPeer(new InetSocketAddress(0));
     }
@@ -123,8 +140,12 @@ private EndpointUri givenServerEndpointUri() {
     }
 
     private RegisterRequest givenRegisterRequestWithEndpoint(String endpoint) {
+        return givenRegisterRequestWithEndpoint(endpoint, LwM2mVersion.V1_1);
+    }
+
+    private RegisterRequest givenRegisterRequestWithEndpoint(String endpoint, LwM2mVersion version) {
         try {
-            return new RegisterRequest(endpoint, 3600l, "1.1", EnumSet.of(BindingMode.U), false, null,
+            return new RegisterRequest(endpoint, 3600l, version.toString(), EnumSet.of(BindingMode.U), false, null,
                     new DefaultLinkParser().parseCoreLinkFormat("</1/0/1>,</2/1>,</3>".getBytes()), null);
         } catch (LinkParseException e) {
             throw new IllegalStateException(e);