diff --git a/doc/unordered/copyright.adoc b/doc/unordered/copyright.adoc
index 0138aa29..180bb2fa 100644
--- a/doc/unordered/copyright.adoc
+++ b/doc/unordered/copyright.adoc
@@ -9,10 +9,10 @@ Copyright (C) 2003, 2004 Jeremy B. Maitin-Shepard
 
 Copyright (C) 2005-2008 Daniel James
 
-Copyright (C) 2022 Christian Mazakas
+Copyright (C) 2022-2023 Christian Mazakas
 
-Copyright (C) 2022 Joaquín M López Muñoz
+Copyright (C) 2022-2023 Joaquín M López Muñoz
 
-Copyright (C) 2022 Peter Dimov
+Copyright (C) 2022-2023 Peter Dimov
 
 Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)