diff --git a/pds4_versions.txt b/pds4_versions.txt
index 8e5fb90..2c92331 100644
--- a/pds4_versions.txt
+++ b/pds4_versions.txt
@@ -3,3 +3,4 @@
 1.20.0.0
 1.21.0.0
 1.22.0.0
+1.23.0.0