diff --git a/build.gradle b/build.gradle
index 80ed642369ace..b731306cef596 100644
--- a/build.gradle
+++ b/build.gradle
@@ -162,8 +162,8 @@ task verifyVersions {
  * after the backport of the backcompat code is complete.
  */
 
-boolean bwc_tests_enabled = true
-final String bwc_tests_disabled_issue = "" /* place a PR link here when committing bwc changes */
+boolean bwc_tests_enabled = false
+final String bwc_tests_disabled_issue = "https://github.com/elastic/elasticsearch/pull/40084" /* place a PR link here when committing bwc changes */
 if (bwc_tests_enabled == false) {
   if (bwc_tests_disabled_issue.isEmpty()) {
     throw new GradleException("bwc_tests_disabled_issue must be set when bwc_tests_enabled == false")
diff --git a/server/src/main/java/org/elasticsearch/search/sort/FieldSortBuilder.java b/server/src/main/java/org/elasticsearch/search/sort/FieldSortBuilder.java
index 5060cea5cf13c..c6e0244cc8011 100644
--- a/server/src/main/java/org/elasticsearch/search/sort/FieldSortBuilder.java
+++ b/server/src/main/java/org/elasticsearch/search/sort/FieldSortBuilder.java
@@ -128,7 +128,7 @@ public FieldSortBuilder(StreamInput in) throws IOException {
         sortMode = in.readOptionalWriteable(SortMode::readFromStream);
         unmappedType = in.readOptionalString();
         nestedSort = in.readOptionalWriteable(NestedSortBuilder::new);
-        if (in.getVersion().onOrAfter(Version.V_8_0_0)) {
+        if (in.getVersion().onOrAfter(Version.V_7_1_0)) {
             numericType = in.readOptionalString();
         }
     }
@@ -143,7 +143,7 @@ public void writeTo(StreamOutput out) throws IOException {
         out.writeOptionalWriteable(sortMode);
         out.writeOptionalString(unmappedType);
         out.writeOptionalWriteable(nestedSort);
-        if (out.getVersion().onOrAfter(Version.V_8_0_0)) {
+        if (out.getVersion().onOrAfter(Version.V_7_1_0)) {
             out.writeOptionalString(numericType);
         }
     }