diff --git a/doc/lambda2/copyright.adoc b/doc/lambda2/copyright.adoc
index 35ad50f..7cd50f2 100644
--- a/doc/lambda2/copyright.adoc
+++ b/doc/lambda2/copyright.adoc
@@ -8,5 +8,5 @@ https://www.boost.org/LICENSE_1_0.txt
 # Copyright and License
 :idprefix:
 
-This documentation is copyright 2020 Peter Dimov and is distributed under
+This documentation is copyright 2020, 2021 Peter Dimov and is distributed under
 the http://www.boost.org/LICENSE_1_0.txt[Boost Software License, Version 1.0].