diff --git a/lucene/backward-codecs/src/test/org/apache/lucene/index/TestBackwardsCompatibility.java b/lucene/backward-codecs/src/test/org/apache/lucene/index/TestBackwardsCompatibility.java
index 8e04143a4f0..0677addc04d 100644
--- a/lucene/backward-codecs/src/test/org/apache/lucene/index/TestBackwardsCompatibility.java
+++ b/lucene/backward-codecs/src/test/org/apache/lucene/index/TestBackwardsCompatibility.java
@@ -236,6 +236,8 @@ public class TestBackwardsCompatibility extends LuceneTestCase {
       "5.4.1-nocfs",
       "5.5.0-cfs",
       "5.5.0-nocfs",
+      "5.5.1-cfs",
+      "5.5.1-nocfs",
       "6.0.0-cfs",
       "6.0.0-nocfs"
   };
diff --git a/lucene/backward-codecs/src/test/org/apache/lucene/index/index.5.5.1-cfs.zip b/lucene/backward-codecs/src/test/org/apache/lucene/index/index.5.5.1-cfs.zip
new file mode 100644
index 00000000000..98e29000f56
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diff --git a/lucene/backward-codecs/src/test/org/apache/lucene/index/index.5.5.1-nocfs.zip b/lucene/backward-codecs/src/test/org/apache/lucene/index/index.5.5.1-nocfs.zip
new file mode 100644
index 00000000000..23929676018
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