Index: src/java/org/apache/lucene/analysis/standard/StandardAnalyzer.java
===================================================================
--- src/java/org/apache/lucene/analysis/standard/StandardAnalyzer.java	(revision 826546)
+++ src/java/org/apache/lucene/analysis/standard/StandardAnalyzer.java	(working copy)
@@ -36,7 +36,7 @@
  * <ul>
  *   <li> As of 2.9, StopFilter preserves position
  *        increments by default
- *   <li> As of 2.9, Tokens incorrectly identified as acronyms
+ *   <li> As of 2.4, Tokens incorrectly identified as acronyms
  *        are corrected (see <a href="https://issues.apache.org/jira/browse/LUCENE-1068">LUCENE-1608</a>
  * </ul>
  *
@@ -259,6 +259,11 @@
     } else {
       useDefaultStopPositionIncrements = true;
     }
+    if (matchVersion.onOrAfter(Version.LUCENE_24)) {
+      replaceInvalidAcronym = defaultReplaceInvalidAcronym;
+    } else {
+      replaceInvalidAcronym = false;
+    }
   }
 
   /** Constructs a {@link StandardTokenizer} filtered by a {@link
Index: src/java/org/apache/lucene/util/Version.java
===================================================================
--- src/java/org/apache/lucene/util/Version.java	(revision 826546)
+++ src/java/org/apache/lucene/util/Version.java	(working copy)
@@ -37,6 +37,18 @@
    */
   public static final Version LUCENE_CURRENT = new Version("LUCENE_CURRENT", 0);
   
+  /** Match settings and bugs in Lucene's 2.0 release. */
+  public static final Version LUCENE_20 = new Version("LUCENE_20", 2000);
+
+  /** Match settings and bugs in Lucene's 2.1 release. */
+  public static final Version LUCENE_21 = new Version("LUCENE_21", 2100);
+
+  /** Match settings and bugs in Lucene's 2.2 release. */
+  public static final Version LUCENE_22 = new Version("LUCENE_22", 2200);
+
+  /** Match settings and bugs in Lucene's 2.3 release. */
+  public static final Version LUCENE_23 = new Version("LUCENE_23", 2300);
+
   /** Match settings and bugs in Lucene's 2.4 release. */
   public static final Version LUCENE_24 = new Version("LUCENE_24", 2400);