diff --git a/byacc.spec b/byacc.spec
index 7496db1..bb2bcf9 100644
--- a/byacc.spec
+++ b/byacc.spec
@@ -1,5 +1,5 @@
 Name:          byacc
-Version:       20210328
+Version:       20210520
 Release:       1mamba
 Summary:       an LALR parser generator.
 Group:         Development/Tools
@@ -52,6 +52,9 @@ make check
 %doc ACKNOWLEDGEMENTS CHANGES NEW_FEATURES NOTES NO_WARRANTY README
 
 %changelog
+* Fri May 21 2021 Automatic Build System <autodist@mambasoft.it> 20210520-1mamba
+- automatic version update by autodist
+
 * Mon Mar 29 2021 Automatic Build System <autodist@mambasoft.it> 20210328-1mamba
 - automatic version update by autodist