diff --git a/src/basic_archive.cpp b/src/basic_archive.cpp
index 01e02a88..8b7d9e95 100644
--- a/src/basic_archive.cpp
+++ b/src/basic_archive.cpp
@@ -83,7 +83,7 @@ BOOST_ARCHIVE_SIGNATURE(){
 // 18- addressed undefined behavior in archive constructors.
 //     init() called from base wrote archive header before archive
 //     was fully constructed.
-//     Boost 1.76 
+// 19- Boost 1.76 April 2021
 
 BOOST_SYMBOL_VISIBLE boost::serialization::library_version_type
 BOOST_ARCHIVE_VERSION(){