[Followup] Store arrays offsets for keyword fields natively with synthetic source

Update index version check after elastic#122997 backport was merged.

Author: martijnvg

server/src/main/java/org/elasticsearch/index/IndexVersions.java

@@ -135,6 +135,7 @@ private static Version parseUnchecked(String version) {
     public static final IndexVersion INFERENCE_METADATA_FIELDS_BACKPORT = def(8_524_0_00, parseUnchecked("9.12.1"));
     public static final IndexVersion LOGSB_OPTIONAL_SORTING_ON_HOST_NAME_BACKPORT = def(8_525_0_00, parseUnchecked("9.12.1"));
     public static final IndexVersion USE_SYNTHETIC_SOURCE_FOR_RECOVERY_BY_DEFAULT_BACKPORT = def(8_526_0_00, parseUnchecked("9.12.1"));
+    public static final IndexVersion SYNTHETIC_SOURCE_STORE_ARRAYS_NATIVELY_KEYWORD_BACKPORT_8_X = def(8_527_0_00, Version.LUCENE_9_12_1);
     public static final IndexVersion UPGRADE_TO_LUCENE_10_0_0 = def(9_000_0_00, Version.LUCENE_10_0_0);
     public static final IndexVersion LOGSDB_DEFAULT_IGNORE_DYNAMIC_BEYOND_LIMIT = def(9_001_0_00, Version.LUCENE_10_0_0);
     public static final IndexVersion TIME_BASED_K_ORDERED_DOC_ID = def(9_002_0_00, Version.LUCENE_10_0_0);

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

@@ -447,7 +447,7 @@ && hasDocValues()
                 && fieldtype.stored() == false
                 && copyTo.copyToFields().isEmpty()
                 && multiFieldsBuilder.hasMultiFields() == false
-                && indexCreatedVersion.onOrAfter(IndexVersions.SYNTHETIC_SOURCE_STORE_ARRAYS_NATIVELY_KEYWORD)) {
+                && indexVersionSupportStoringArraysNatively()) {
                 // Skip stored, we will be synthesizing from stored fields, no point to keep track of the offsets
                 // Skip copy_to and multi fields, supporting that requires more work. However, copy_to usage is rare in metrics and
                 // logging use cases
@@ -472,6 +472,14 @@ && hasDocValues()
             );
         }
 
+        private boolean indexVersionSupportStoringArraysNatively() {
+            return indexCreatedVersion.onOrAfter(IndexVersions.SYNTHETIC_SOURCE_STORE_ARRAYS_NATIVELY_KEYWORD)
+                || indexCreatedVersion.between(
+                    IndexVersions.SYNTHETIC_SOURCE_STORE_ARRAYS_NATIVELY_KEYWORD_BACKPORT_8_X,
+                    IndexVersions.UPGRADE_TO_LUCENE_10_0_0
+                );
+        }
+
         private FieldType resolveFieldType(
             final boolean useDocValuesSkipper,
             final IndexVersion indexCreatedVersion,