Adapt bwc version after backport

Relates #34225

server/src/main/java/org/elasticsearch/index/mapper/ParseContext.java

@@ -458,9 +458,9 @@ public abstract class ParseContext implements Iterable<ParseContext.Document>{
         void postParse() {
             if (documents.size() > 1) {
                 docsReversed = true;
-                if (indexSettings.getIndexVersionCreated().onOrAfter(Version.V_7_0_0_alpha1)) {
+                if (indexSettings.getIndexVersionCreated().onOrAfter(Version.V_6_5_0)) {
                     /**
-                     * For indices created on or after {@link Version#V_7_0_0_alpha1} we preserve the order
+                     * For indices created on or after {@link Version#V_6_5_0} we preserve the order
                      * of the children while ensuring that parents appear after them.
                      */
                     List<Document> newDocs = reorderParent(documents);

server/src/test/java/org/elasticsearch/index/mapper/NestedObjectMapperTests.java

@@ -651,8 +651,8 @@ public class NestedObjectMapperTests extends ESSingleNodeTestCase {
             .endObject().endObject().endObject());
 
         Version bwcVersion = VersionUtils.randomVersionBetween(random(), Version.V_6_0_0,
-            Version.V_7_0_0_alpha1.minimumCompatibilityVersion());
-        for (Version version : new Version[] {Version.V_7_0_0_alpha1, bwcVersion}) {
+            Version.V_6_5_0);
+        for (Version version : new Version[] {Version.V_6_5_0, bwcVersion}) {
             DocumentMapper docMapper = createIndex("test-" + version,
                 Settings.builder().put(IndexMetaData.SETTING_INDEX_VERSION_CREATED.getKey(), version).build())
                     .mapperService().documentMapperParser().parse("type", new CompressedXContent(mapping));
@@ -679,7 +679,7 @@ public class NestedObjectMapperTests extends ESSingleNodeTestCase {
                 XContentType.JSON));
 
             assertThat(doc.docs().size(), equalTo(3));
-            if (version.onOrAfter(Version.V_7_0_0_alpha1)) {
+            if (version.onOrAfter(Version.V_6_5_0)) {
                 assertThat(doc.docs().get(0).get(TypeFieldMapper.NAME), equalTo(nested1Mapper.nestedTypePathAsString()));
                 assertThat(doc.docs().get(0).get("nested1.field1"), equalTo("1"));
                 assertThat(doc.docs().get(0).get("nested1.field2"), equalTo("2"));