diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 727445222..c06d8560e 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -1,4 +1,5 @@
-# Copyright 2025 Nana Sakisaka
+# Copyright 2025-2026 Nana Sakisaka
+# Copyright 2026 The Iris Project Contributors
 #
 # Distributed under the Boost Software License, Version 1.0.
 # https://www.boost.org/LICENSE_1_0.txt
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4e71049a9..bc6c06d0f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,5 +1,6 @@
 # Copyright 2020 Peter Dimov
 # Copyright 2025-2026 Nana Sakisaka
+# Copyright 2026 The Iris Project Contributors
 #
 # Distributed under the Boost Software License, Version 1.0.
 # https://www.boost.org/LICENSE_1_0.txt
diff --git a/include/iris/x4.hpp b/include/iris/x4.hpp
index b7323e803..84ab687bc 100644
--- a/include/iris/x4.hpp
+++ b/include/iris/x4.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2013 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/allocator.hpp b/include/iris/x4/allocator.hpp
index 4d7061bf0..f1d0de892 100644
--- a/include/iris/x4/allocator.hpp
+++ b/include/iris/x4/allocator.hpp
@@ -3,6 +3,7 @@
 
 /*=============================================================================
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/ast/position_tagged.hpp b/include/iris/x4/ast/position_tagged.hpp
index 21a4c9b2c..afb0be613 100644
--- a/include/iris/x4/ast/position_tagged.hpp
+++ b/include/iris/x4/ast/position_tagged.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/auxiliary.hpp b/include/iris/x4/auxiliary.hpp
index d605700a3..4400b903c 100644
--- a/include/iris/x4/auxiliary.hpp
+++ b/include/iris/x4/auxiliary.hpp
@@ -5,6 +5,7 @@
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2001-2011 Hartmut Kaiser
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/auxiliary/attr.hpp b/include/iris/x4/auxiliary/attr.hpp
index 671e6ec68..b17e5f31f 100644
--- a/include/iris/x4/auxiliary/attr.hpp
+++ b/include/iris/x4/auxiliary/attr.hpp
@@ -6,6 +6,7 @@
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2013 Agustin Berge
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/auxiliary/eoi.hpp b/include/iris/x4/auxiliary/eoi.hpp
index e139221de..92fb6b28d 100644
--- a/include/iris/x4/auxiliary/eoi.hpp
+++ b/include/iris/x4/auxiliary/eoi.hpp
@@ -5,6 +5,7 @@
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2001-2011 Hartmut Kaiser
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/auxiliary/eol.hpp b/include/iris/x4/auxiliary/eol.hpp
index 46bd0872a..d5fb0ca61 100644
--- a/include/iris/x4/auxiliary/eol.hpp
+++ b/include/iris/x4/auxiliary/eol.hpp
@@ -5,6 +5,7 @@
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2001-2011 Hartmut Kaiser
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/auxiliary/eps.hpp b/include/iris/x4/auxiliary/eps.hpp
index 3d18208d6..137221928 100644
--- a/include/iris/x4/auxiliary/eps.hpp
+++ b/include/iris/x4/auxiliary/eps.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/char.hpp b/include/iris/x4/char.hpp
index 9ee3b7261..8a2b873a1 100644
--- a/include/iris/x4/char.hpp
+++ b/include/iris/x4/char.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/char/any_char.hpp b/include/iris/x4/char/any_char.hpp
index 65647d7a3..1d4b359ba 100644
--- a/include/iris/x4/char/any_char.hpp
+++ b/include/iris/x4/char/any_char.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/char/char.hpp b/include/iris/x4/char/char.hpp
index d7270723c..948802958 100644
--- a/include/iris/x4/char/char.hpp
+++ b/include/iris/x4/char/char.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/char/char_class.hpp b/include/iris/x4/char/char_class.hpp
index 37840deac..56832f351 100644
--- a/include/iris/x4/char/char_class.hpp
+++ b/include/iris/x4/char/char_class.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/char/char_class_tags.hpp b/include/iris/x4/char/char_class_tags.hpp
index eb8951bcf..862649eab 100644
--- a/include/iris/x4/char/char_class_tags.hpp
+++ b/include/iris/x4/char/char_class_tags.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/char/char_parser.hpp b/include/iris/x4/char/char_parser.hpp
index b0d07df15..50e6ffddd 100644
--- a/include/iris/x4/char/char_parser.hpp
+++ b/include/iris/x4/char/char_parser.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/char/char_set.hpp b/include/iris/x4/char/char_set.hpp
index 2e3a641c1..195f15d39 100644
--- a/include/iris/x4/char/char_set.hpp
+++ b/include/iris/x4/char/char_set.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/char/detail/basic_chset.hpp b/include/iris/x4/char/detail/basic_chset.hpp
index e90f6e528..81eae5e13 100644
--- a/include/iris/x4/char/detail/basic_chset.hpp
+++ b/include/iris/x4/char/detail/basic_chset.hpp
@@ -5,6 +5,7 @@
     Copyright (c) 2001-2011 Joel de Guzman
     Copyright (c) 2001-2009 Daniel Nuffer
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/char/detail/cast_char.hpp b/include/iris/x4/char/detail/cast_char.hpp
index 4b49e40b8..38a90f2c8 100644
--- a/include/iris/x4/char/detail/cast_char.hpp
+++ b/include/iris/x4/char/detail/cast_char.hpp
@@ -5,6 +5,7 @@
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2001-2011 Hartmut Kaiser
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/char/detail/char_range.hpp b/include/iris/x4/char/detail/char_range.hpp
index cafe1f089..dd32de268 100644
--- a/include/iris/x4/char/detail/char_range.hpp
+++ b/include/iris/x4/char/detail/char_range.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2011 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/char/detail/char_range_functions.hpp b/include/iris/x4/char/detail/char_range_functions.hpp
index 5051302f8..52c4c21c2 100644
--- a/include/iris/x4/char/detail/char_range_functions.hpp
+++ b/include/iris/x4/char/detail/char_range_functions.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2011 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/char/detail/char_range_run.hpp b/include/iris/x4/char/detail/char_range_run.hpp
index 6962c0b6a..8b1e013d0 100644
--- a/include/iris/x4/char/detail/char_range_run.hpp
+++ b/include/iris/x4/char/detail/char_range_run.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2011 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/char/literal_char.hpp b/include/iris/x4/char/literal_char.hpp
index c0ed69fac..8a8c0dbe2 100644
--- a/include/iris/x4/char/literal_char.hpp
+++ b/include/iris/x4/char/literal_char.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/char/negated_char.hpp b/include/iris/x4/char/negated_char.hpp
index 9c0c9cbb6..af50b92f8 100644
--- a/include/iris/x4/char/negated_char.hpp
+++ b/include/iris/x4/char/negated_char.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/char/unicode_char_class.hpp b/include/iris/x4/char/unicode_char_class.hpp
index ad8f51832..9efe5bb52 100644
--- a/include/iris/x4/char/unicode_char_class.hpp
+++ b/include/iris/x4/char/unicode_char_class.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/char_encoding/standard.hpp b/include/iris/x4/char_encoding/standard.hpp
index b5284ef0e..d1b730346 100644
--- a/include/iris/x4/char_encoding/standard.hpp
+++ b/include/iris/x4/char_encoding/standard.hpp
@@ -5,6 +5,7 @@
     Copyright (c) 2001-2011 Hartmut Kaiser
     Copyright (c) 2001-2011 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/char_encoding/standard_wide.hpp b/include/iris/x4/char_encoding/standard_wide.hpp
index 75c23f793..f2b4059d4 100644
--- a/include/iris/x4/char_encoding/standard_wide.hpp
+++ b/include/iris/x4/char_encoding/standard_wide.hpp
@@ -5,6 +5,7 @@
     Copyright (c) 2001-2011 Hartmut Kaiser
     Copyright (c) 2001-2011 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/char_encoding/unicode.hpp b/include/iris/x4/char_encoding/unicode.hpp
index cd033f501..4779db1f9 100644
--- a/include/iris/x4/char_encoding/unicode.hpp
+++ b/include/iris/x4/char_encoding/unicode.hpp
@@ -5,6 +5,7 @@
     Copyright (c) 2001-2011 Hartmut Kaiser
     Copyright (c) 2001-2011 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/char_encoding/unicode/classification.hpp b/include/iris/x4/char_encoding/unicode/classification.hpp
index eecc9444e..9c8c1a72d 100644
--- a/include/iris/x4/char_encoding/unicode/classification.hpp
+++ b/include/iris/x4/char_encoding/unicode/classification.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2011 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/char_encoding/unicode/detail/category_table.hpp b/include/iris/x4/char_encoding/unicode/detail/category_table.hpp
index 548729f65..95663f293 100644
--- a/include/iris/x4/char_encoding/unicode/detail/category_table.hpp
+++ b/include/iris/x4/char_encoding/unicode/detail/category_table.hpp
@@ -1,6 +1,7 @@
 /*=============================================================================
     Copyright (c) 2001-2011 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/char_encoding/unicode/detail/lowercase_table.hpp b/include/iris/x4/char_encoding/unicode/detail/lowercase_table.hpp
index b4cd70700..0337f8a83 100644
--- a/include/iris/x4/char_encoding/unicode/detail/lowercase_table.hpp
+++ b/include/iris/x4/char_encoding/unicode/detail/lowercase_table.hpp
@@ -1,6 +1,7 @@
 /*=============================================================================
     Copyright (c) 2001-2011 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/char_encoding/unicode/detail/script_table.hpp b/include/iris/x4/char_encoding/unicode/detail/script_table.hpp
index d96831e53..42c616ddf 100644
--- a/include/iris/x4/char_encoding/unicode/detail/script_table.hpp
+++ b/include/iris/x4/char_encoding/unicode/detail/script_table.hpp
@@ -1,6 +1,7 @@
 /*=============================================================================
     Copyright (c) 2001-2011 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/char_encoding/unicode/detail/uppercase_table.hpp b/include/iris/x4/char_encoding/unicode/detail/uppercase_table.hpp
index 1adcd6875..3496512b7 100644
--- a/include/iris/x4/char_encoding/unicode/detail/uppercase_table.hpp
+++ b/include/iris/x4/char_encoding/unicode/detail/uppercase_table.hpp
@@ -1,6 +1,7 @@
 /*=============================================================================
     Copyright (c) 2001-2011 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/core/action.hpp b/include/iris/x4/core/action.hpp
index 2ff18f209..1af26c861 100644
--- a/include/iris/x4/core/action.hpp
+++ b/include/iris/x4/core/action.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/core/action_context.hpp b/include/iris/x4/core/action_context.hpp
index 847c0651f..4bc106d68 100644
--- a/include/iris/x4/core/action_context.hpp
+++ b/include/iris/x4/core/action_context.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/core/attribute.hpp b/include/iris/x4/core/attribute.hpp
index 225a2b38c..5cf5e12d0 100644
--- a/include/iris/x4/core/attribute.hpp
+++ b/include/iris/x4/core/attribute.hpp
@@ -3,6 +3,7 @@
 
 /*=============================================================================
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/core/container_appender.hpp b/include/iris/x4/core/container_appender.hpp
index 1631d021e..624390598 100644
--- a/include/iris/x4/core/container_appender.hpp
+++ b/include/iris/x4/core/container_appender.hpp
@@ -1,6 +1,14 @@
 #ifndef IRIS_X4_CORE_CONTAINER_APPENDER_HPP
 #define IRIS_X4_CORE_CONTAINER_APPENDER_HPP
 
+/*=============================================================================
+    Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
+
+    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)
+=============================================================================*/
+
 #include <iris/config.hpp>
 #include <iris/type_traits.hpp>
 
diff --git a/include/iris/x4/core/context.hpp b/include/iris/x4/core/context.hpp
index 61feb651d..37fc269de 100644
--- a/include/iris/x4/core/context.hpp
+++ b/include/iris/x4/core/context.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/core/detail/parse_alternative.hpp b/include/iris/x4/core/detail/parse_alternative.hpp
index 925516025..07d3e6924 100644
--- a/include/iris/x4/core/detail/parse_alternative.hpp
+++ b/include/iris/x4/core/detail/parse_alternative.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/core/detail/parse_into_container.hpp b/include/iris/x4/core/detail/parse_into_container.hpp
index 1ec5a1af4..8b8e084ae 100644
--- a/include/iris/x4/core/detail/parse_into_container.hpp
+++ b/include/iris/x4/core/detail/parse_into_container.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/core/detail/parse_sequence.hpp b/include/iris/x4/core/detail/parse_sequence.hpp
index a2194e3bd..b2aba10f2 100644
--- a/include/iris/x4/core/detail/parse_sequence.hpp
+++ b/include/iris/x4/core/detail/parse_sequence.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/core/expectation.hpp b/include/iris/x4/core/expectation.hpp
index 6cd3d7b67..8d545f2c8 100644
--- a/include/iris/x4/core/expectation.hpp
+++ b/include/iris/x4/core/expectation.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2017 wanghan02
     Copyright (c) 2024-2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/core/move_to.hpp b/include/iris/x4/core/move_to.hpp
index d763f44ee..ee30e797c 100644
--- a/include/iris/x4/core/move_to.hpp
+++ b/include/iris/x4/core/move_to.hpp
@@ -5,6 +5,7 @@
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2013 Agustin Berge
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/core/parser.hpp b/include/iris/x4/core/parser.hpp
index d72bca9ca..ede66cca2 100644
--- a/include/iris/x4/core/parser.hpp
+++ b/include/iris/x4/core/parser.hpp
@@ -5,6 +5,7 @@
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2013 Agustin Berge
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/core/parser_traits.hpp b/include/iris/x4/core/parser_traits.hpp
index c34333a38..85d2ce501 100644
--- a/include/iris/x4/core/parser_traits.hpp
+++ b/include/iris/x4/core/parser_traits.hpp
@@ -1,6 +1,14 @@
 #ifndef IRIS_X4_CORE_PARSER_TRAITS_HPP
 #define IRIS_X4_CORE_PARSER_TRAITS_HPP
 
+/*=============================================================================
+    Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
+
+    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)
+==============================================================================*/
+
 #include <iris/config.hpp>
 
 #include <type_traits>
diff --git a/include/iris/x4/core/skip_over.hpp b/include/iris/x4/core/skip_over.hpp
index ebae70783..f01886643 100644
--- a/include/iris/x4/core/skip_over.hpp
+++ b/include/iris/x4/core/skip_over.hpp
@@ -5,6 +5,7 @@
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2017 wanghan02
     Copyright (c) 2024-2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/core/unused.hpp b/include/iris/x4/core/unused.hpp
index ca832d72f..100cf2034 100644
--- a/include/iris/x4/core/unused.hpp
+++ b/include/iris/x4/core/unused.hpp
@@ -5,6 +5,7 @@
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2001-2011 Hartmut Kaiser
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/debug/annotate_on_success.hpp b/include/iris/x4/debug/annotate_on_success.hpp
index e457ac056..06fae6777 100644
--- a/include/iris/x4/debug/annotate_on_success.hpp
+++ b/include/iris/x4/debug/annotate_on_success.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2015 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/debug/debug_handler_state.hpp b/include/iris/x4/debug/debug_handler_state.hpp
index d4b61aad4..2d89aec4f 100644
--- a/include/iris/x4/debug/debug_handler_state.hpp
+++ b/include/iris/x4/debug/debug_handler_state.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/debug/detail/parse_callback.hpp b/include/iris/x4/debug/detail/parse_callback.hpp
index 3edeb0d0d..29db70bd4 100644
--- a/include/iris/x4/debug/detail/parse_callback.hpp
+++ b/include/iris/x4/debug/detail/parse_callback.hpp
@@ -3,6 +3,7 @@
 
 /*=============================================================================
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/debug/error_reporting.hpp b/include/iris/x4/debug/error_reporting.hpp
index 3114b84be..b240e7978 100644
--- a/include/iris/x4/debug/error_reporting.hpp
+++ b/include/iris/x4/debug/error_reporting.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/debug/print_attribute.hpp b/include/iris/x4/debug/print_attribute.hpp
index 9cab90b7e..10978c1bd 100644
--- a/include/iris/x4/debug/print_attribute.hpp
+++ b/include/iris/x4/debug/print_attribute.hpp
@@ -5,6 +5,7 @@
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2001-2011 Hartmut Kaiser
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/debug/print_token.hpp b/include/iris/x4/debug/print_token.hpp
index af054e376..c7696c963 100644
--- a/include/iris/x4/debug/print_token.hpp
+++ b/include/iris/x4/debug/print_token.hpp
@@ -5,6 +5,7 @@
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2001-2011 Hartmut Kaiser
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/debug/simple_trace.hpp b/include/iris/x4/debug/simple_trace.hpp
index f16afb6a0..ba793e4b1 100644
--- a/include/iris/x4/debug/simple_trace.hpp
+++ b/include/iris/x4/debug/simple_trace.hpp
@@ -5,6 +5,7 @@
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2001-2011 Hartmut Kaiser
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/directive.hpp b/include/iris/x4/directive.hpp
index 36c4d6352..896262bdb 100644
--- a/include/iris/x4/directive.hpp
+++ b/include/iris/x4/directive.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2015 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/directive/as.hpp b/include/iris/x4/directive/as.hpp
index 62cae1680..0b5209efc 100644
--- a/include/iris/x4/directive/as.hpp
+++ b/include/iris/x4/directive/as.hpp
@@ -1,6 +1,14 @@
 #ifndef IRIS_X4_DIRECTIVE_AS_HPP
 #define IRIS_X4_DIRECTIVE_AS_HPP
 
+/*=============================================================================
+    Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
+
+    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)
+=============================================================================*/
+
 #include <iris/x4/core/parser.hpp>
 #include <iris/x4/core/move_to.hpp>
 #include <iris/x4/core/unused.hpp>
diff --git a/include/iris/x4/directive/expect.hpp b/include/iris/x4/directive/expect.hpp
index b652e17af..cd2c4acfa 100644
--- a/include/iris/x4/directive/expect.hpp
+++ b/include/iris/x4/directive/expect.hpp
@@ -5,6 +5,7 @@
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2017 wanghan02
     Copyright (c) 2024-2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/directive/lexeme.hpp b/include/iris/x4/directive/lexeme.hpp
index 00a750525..21ee08ded 100644
--- a/include/iris/x4/directive/lexeme.hpp
+++ b/include/iris/x4/directive/lexeme.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/directive/matches.hpp b/include/iris/x4/directive/matches.hpp
index 07d8884f3..0cd981348 100644
--- a/include/iris/x4/directive/matches.hpp
+++ b/include/iris/x4/directive/matches.hpp
@@ -6,6 +6,7 @@
     Copyright (c) 2001-2011 Hartmut Kaiser
     Copyright (c) 2017 wanghan02
     Copyright (c) 2024-2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/directive/no_case.hpp b/include/iris/x4/directive/no_case.hpp
index 5238ed3c7..b4b978ec5 100644
--- a/include/iris/x4/directive/no_case.hpp
+++ b/include/iris/x4/directive/no_case.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2014 Thomas Bernard
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/directive/no_skip.hpp b/include/iris/x4/directive/no_skip.hpp
index c7b710d00..4ce718690 100644
--- a/include/iris/x4/directive/no_skip.hpp
+++ b/include/iris/x4/directive/no_skip.hpp
@@ -6,6 +6,7 @@
     Copyright (c) 2001-2011 Hartmut Kaiser
     Copyright (c) 2013 Agustin Berge
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/directive/omit.hpp b/include/iris/x4/directive/omit.hpp
index 000a57e10..5574adf3f 100644
--- a/include/iris/x4/directive/omit.hpp
+++ b/include/iris/x4/directive/omit.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/directive/raw.hpp b/include/iris/x4/directive/raw.hpp
index c38084851..8eb971d72 100644
--- a/include/iris/x4/directive/raw.hpp
+++ b/include/iris/x4/directive/raw.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/directive/repeat.hpp b/include/iris/x4/directive/repeat.hpp
index eeb31ca7d..fe728736b 100644
--- a/include/iris/x4/directive/repeat.hpp
+++ b/include/iris/x4/directive/repeat.hpp
@@ -7,6 +7,7 @@
     Copyright (c) 2014 Thomas Bernard
     Copyright (c) 2017 wanghan02
     Copyright (c) 2024-2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/directive/seek.hpp b/include/iris/x4/directive/seek.hpp
index b7d5a5969..7bc676829 100644
--- a/include/iris/x4/directive/seek.hpp
+++ b/include/iris/x4/directive/seek.hpp
@@ -5,7 +5,8 @@
     Copyright (c) 2011 Jamboree
     Copyright (c) 2014 Lee Clagett
     Copyright (c) 2017 wanghan02
-    Copyright (c) 2024 Nana Sakisaka
+    Copyright (c) 2024-2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/directive/skip.hpp b/include/iris/x4/directive/skip.hpp
index b6766d9a1..f4d336eba 100644
--- a/include/iris/x4/directive/skip.hpp
+++ b/include/iris/x4/directive/skip.hpp
@@ -5,6 +5,7 @@
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2013 Agustin Berge
     Copyright (c) 2024-2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/directive/with.hpp b/include/iris/x4/directive/with.hpp
index 7c7dd9a2e..a7331ed0e 100644
--- a/include/iris/x4/directive/with.hpp
+++ b/include/iris/x4/directive/with.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/directive/with_local.hpp b/include/iris/x4/directive/with_local.hpp
index 8b0da22dd..99b84d494 100644
--- a/include/iris/x4/directive/with_local.hpp
+++ b/include/iris/x4/directive/with_local.hpp
@@ -1,6 +1,14 @@
 #ifndef IRIS_X4_DIRECTIVE_WITH_LOCAL_HPP
 #define IRIS_X4_DIRECTIVE_WITH_LOCAL_HPP
 
+/*=============================================================================
+    Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
+
+    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)
+=============================================================================*/
+
 #include <iris/x4/core/parser.hpp>
 #include <iris/x4/core/context.hpp>
 
diff --git a/include/iris/x4/numeric.hpp b/include/iris/x4/numeric.hpp
index 7199fb6d3..ddb2f97bd 100644
--- a/include/iris/x4/numeric.hpp
+++ b/include/iris/x4/numeric.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/numeric/bool.hpp b/include/iris/x4/numeric/bool.hpp
index e8a2e294b..34be02807 100644
--- a/include/iris/x4/numeric/bool.hpp
+++ b/include/iris/x4/numeric/bool.hpp
@@ -5,6 +5,7 @@
     Copyright (c) 2009 Hartmut Kaiser
     Copyright (c) 2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/numeric/int.hpp b/include/iris/x4/numeric/int.hpp
index 4967b7f0b..13d18db9b 100644
--- a/include/iris/x4/numeric/int.hpp
+++ b/include/iris/x4/numeric/int.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/numeric/real.hpp b/include/iris/x4/numeric/real.hpp
index 49d7f43b1..6792bba9c 100644
--- a/include/iris/x4/numeric/real.hpp
+++ b/include/iris/x4/numeric/real.hpp
@@ -5,6 +5,7 @@
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2001-2011 Hartmut Kaiser
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/numeric/uint.hpp b/include/iris/x4/numeric/uint.hpp
index ca6aea44c..f33827c2b 100644
--- a/include/iris/x4/numeric/uint.hpp
+++ b/include/iris/x4/numeric/uint.hpp
@@ -5,6 +5,7 @@
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2011 Jan Frederick Eick
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/numeric/utils/extract_int.hpp b/include/iris/x4/numeric/utils/extract_int.hpp
index 9187f1e3e..090b95c00 100644
--- a/include/iris/x4/numeric/utils/extract_int.hpp
+++ b/include/iris/x4/numeric/utils/extract_int.hpp
@@ -8,6 +8,7 @@
     Copyright (c) 2011 Christopher Jefferson
     Copyright (c) 2006 Stephen Nutt
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/numeric/utils/extract_real.hpp b/include/iris/x4/numeric/utils/extract_real.hpp
index 729a92974..fedd62d4d 100644
--- a/include/iris/x4/numeric/utils/extract_real.hpp
+++ b/include/iris/x4/numeric/utils/extract_real.hpp
@@ -5,6 +5,7 @@
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2001-2011 Hartmut Kaiser
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/numeric/utils/pow10.hpp b/include/iris/x4/numeric/utils/pow10.hpp
index 4a5489a76..ed8d3b25e 100644
--- a/include/iris/x4/numeric/utils/pow10.hpp
+++ b/include/iris/x4/numeric/utils/pow10.hpp
@@ -5,6 +5,7 @@
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2001-2011 Hartmut Kaiser
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/operator.hpp b/include/iris/x4/operator.hpp
index 414b9c9ff..798ece7be 100644
--- a/include/iris/x4/operator.hpp
+++ b/include/iris/x4/operator.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/operator/alternative.hpp b/include/iris/x4/operator/alternative.hpp
index c3dc061e7..6f70dd6e0 100644
--- a/include/iris/x4/operator/alternative.hpp
+++ b/include/iris/x4/operator/alternative.hpp
@@ -5,6 +5,7 @@
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2017 wanghan02
     Copyright (c) 2024-2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/operator/and_predicate.hpp b/include/iris/x4/operator/and_predicate.hpp
index 9166b1a36..d0a8b70c7 100644
--- a/include/iris/x4/operator/and_predicate.hpp
+++ b/include/iris/x4/operator/and_predicate.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/operator/difference.hpp b/include/iris/x4/operator/difference.hpp
index 39499e7b3..b81144b12 100644
--- a/include/iris/x4/operator/difference.hpp
+++ b/include/iris/x4/operator/difference.hpp
@@ -5,6 +5,7 @@
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2017 wanghan02
     Copyright (c) 2024-2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/operator/kleene.hpp b/include/iris/x4/operator/kleene.hpp
index b2f5ed798..8589e2a8c 100644
--- a/include/iris/x4/operator/kleene.hpp
+++ b/include/iris/x4/operator/kleene.hpp
@@ -6,6 +6,7 @@
     Copyright (c) 2001-2011 Hartmut Kaiser
     Copyright (c) 2017 wanghan02
     Copyright (c) 2024-2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/operator/list.hpp b/include/iris/x4/operator/list.hpp
index ec720ca18..1fc2589ab 100644
--- a/include/iris/x4/operator/list.hpp
+++ b/include/iris/x4/operator/list.hpp
@@ -6,6 +6,7 @@
     Copyright (c) 2001-2011 Hartmut Kaiser
     Copyright (c) 2017 wanghan02
     Copyright (c) 2024-2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/operator/not_predicate.hpp b/include/iris/x4/operator/not_predicate.hpp
index 8e734d950..9da65fc17 100644
--- a/include/iris/x4/operator/not_predicate.hpp
+++ b/include/iris/x4/operator/not_predicate.hpp
@@ -5,6 +5,7 @@
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2017 wanghan02
     Copyright (c) 2024-2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/operator/optional.hpp b/include/iris/x4/operator/optional.hpp
index e777dc639..946b3e2f5 100644
--- a/include/iris/x4/operator/optional.hpp
+++ b/include/iris/x4/operator/optional.hpp
@@ -6,6 +6,7 @@
     Copyright (c) 2001-2011 Hartmut Kaiser
     Copyright (c) 2017 wanghan02
     Copyright (c) 2024-2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/operator/plus.hpp b/include/iris/x4/operator/plus.hpp
index 8683e39fa..c512a2364 100644
--- a/include/iris/x4/operator/plus.hpp
+++ b/include/iris/x4/operator/plus.hpp
@@ -6,6 +6,7 @@
     Copyright (c) 2001-2011 Hartmut Kaiser
     Copyright (c) 2017 wanghan02
     Copyright (c) 2024-2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/operator/sequence.hpp b/include/iris/x4/operator/sequence.hpp
index d5ac47758..949b66141 100644
--- a/include/iris/x4/operator/sequence.hpp
+++ b/include/iris/x4/operator/sequence.hpp
@@ -5,6 +5,7 @@
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2017 wanghan02
     Copyright (c) 2024-2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/parse.hpp b/include/iris/x4/parse.hpp
index ae6e0326f..6dd5bc069 100644
--- a/include/iris/x4/parse.hpp
+++ b/include/iris/x4/parse.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/parse_result.hpp b/include/iris/x4/parse_result.hpp
index 26e605ade..3ed317a97 100644
--- a/include/iris/x4/parse_result.hpp
+++ b/include/iris/x4/parse_result.hpp
@@ -3,6 +3,7 @@
 
 /*=============================================================================
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/rule.hpp b/include/iris/x4/rule.hpp
index 1014f1dcd..dd92982b4 100644
--- a/include/iris/x4/rule.hpp
+++ b/include/iris/x4/rule.hpp
@@ -5,6 +5,7 @@
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2017 wanghan02
     Copyright (c) 2024-2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/string.hpp b/include/iris/x4/string.hpp
index a75cecf84..79019dd75 100644
--- a/include/iris/x4/string.hpp
+++ b/include/iris/x4/string.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/string/case_compare.hpp b/include/iris/x4/string/case_compare.hpp
index b987a3884..aeb48f4d0 100644
--- a/include/iris/x4/string/case_compare.hpp
+++ b/include/iris/x4/string/case_compare.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/string/detail/string_parse.hpp b/include/iris/x4/string/detail/string_parse.hpp
index a88d06e1f..120a03ddd 100644
--- a/include/iris/x4/string/detail/string_parse.hpp
+++ b/include/iris/x4/string/detail/string_parse.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/string/detail/tst_node.hpp b/include/iris/x4/string/detail/tst_node.hpp
index 853843657..d82864a64 100644
--- a/include/iris/x4/string/detail/tst_node.hpp
+++ b/include/iris/x4/string/detail/tst_node.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/string/literal_string.hpp b/include/iris/x4/string/literal_string.hpp
index 3f0ad96f0..51f5446da 100644
--- a/include/iris/x4/string/literal_string.hpp
+++ b/include/iris/x4/string/literal_string.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/string/string.hpp b/include/iris/x4/string/string.hpp
index 88f54c82a..540aaff44 100644
--- a/include/iris/x4/string/string.hpp
+++ b/include/iris/x4/string/string.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/string/tst.hpp b/include/iris/x4/string/tst.hpp
index edaf1c863..38df327e0 100644
--- a/include/iris/x4/string/tst.hpp
+++ b/include/iris/x4/string/tst.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/string/utf8.hpp b/include/iris/x4/string/utf8.hpp
index 6aa4b8491..034e6b535 100644
--- a/include/iris/x4/string/utf8.hpp
+++ b/include/iris/x4/string/utf8.hpp
@@ -5,6 +5,7 @@
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2023 Nikita Kniazev
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/symbols.hpp b/include/iris/x4/symbols.hpp
index dce59bc64..49a3f95f0 100644
--- a/include/iris/x4/symbols.hpp
+++ b/include/iris/x4/symbols.hpp
@@ -5,6 +5,7 @@
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2013 Carl Barron
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/traits/attribute_category.hpp b/include/iris/x4/traits/attribute_category.hpp
index 4338cb785..f347abdc1 100644
--- a/include/iris/x4/traits/attribute_category.hpp
+++ b/include/iris/x4/traits/attribute_category.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/traits/attribute_of_binary.hpp b/include/iris/x4/traits/attribute_of_binary.hpp
index 9090f246b..0628e2429 100644
--- a/include/iris/x4/traits/attribute_of_binary.hpp
+++ b/include/iris/x4/traits/attribute_of_binary.hpp
@@ -6,6 +6,7 @@
     Copyright (c) 2013 Agustin Berge
     Copyright (c) 2020 Nikita Kniazev
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/traits/char_encoding_traits.hpp b/include/iris/x4/traits/char_encoding_traits.hpp
index 989f95920..43596e5cf 100644
--- a/include/iris/x4/traits/char_encoding_traits.hpp
+++ b/include/iris/x4/traits/char_encoding_traits.hpp
@@ -3,6 +3,7 @@
 
 /*=============================================================================
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/traits/container_traits.hpp b/include/iris/x4/traits/container_traits.hpp
index 770e19ca3..a46272f63 100644
--- a/include/iris/x4/traits/container_traits.hpp
+++ b/include/iris/x4/traits/container_traits.hpp
@@ -5,6 +5,7 @@
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2001-2011 Hartmut Kaiser
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/traits/numeric_traits.hpp b/include/iris/x4/traits/numeric_traits.hpp
index d185ce186..a7844b74a 100644
--- a/include/iris/x4/traits/numeric_traits.hpp
+++ b/include/iris/x4/traits/numeric_traits.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2011 Hartmut Kaiser
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/traits/optional_traits.hpp b/include/iris/x4/traits/optional_traits.hpp
index 6839b8b07..7735778ef 100644
--- a/include/iris/x4/traits/optional_traits.hpp
+++ b/include/iris/x4/traits/optional_traits.hpp
@@ -5,6 +5,7 @@
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2001-2011 Hartmut Kaiser
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/traits/string_traits.hpp b/include/iris/x4/traits/string_traits.hpp
index 1887d507c..0cc711e4a 100644
--- a/include/iris/x4/traits/string_traits.hpp
+++ b/include/iris/x4/traits/string_traits.hpp
@@ -6,6 +6,7 @@
     Copyright (c) 2001-2011 Hartmut Kaiser
     Copyright (c) 2010 Bryce Lelbach
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/traits/subrange_traits.hpp b/include/iris/x4/traits/subrange_traits.hpp
index d992f1bba..f57439b97 100644
--- a/include/iris/x4/traits/subrange_traits.hpp
+++ b/include/iris/x4/traits/subrange_traits.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/traits/substitution.hpp b/include/iris/x4/traits/substitution.hpp
index 7521ebf26..387343517 100644
--- a/include/iris/x4/traits/substitution.hpp
+++ b/include/iris/x4/traits/substitution.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/traits/transform_attribute.hpp b/include/iris/x4/traits/transform_attribute.hpp
index 8c4aa103a..450dac785 100644
--- a/include/iris/x4/traits/transform_attribute.hpp
+++ b/include/iris/x4/traits/transform_attribute.hpp
@@ -5,6 +5,7 @@
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2001-2012 Hartmut Kaiser
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/traits/tuple_traits.hpp b/include/iris/x4/traits/tuple_traits.hpp
index 8bc5d53f2..bd277ff09 100644
--- a/include/iris/x4/traits/tuple_traits.hpp
+++ b/include/iris/x4/traits/tuple_traits.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/include/iris/x4/traits/variant_traits.hpp b/include/iris/x4/traits/variant_traits.hpp
index b6a27cf91..d5484e92d 100644
--- a/include/iris/x4/traits/variant_traits.hpp
+++ b/include/iris/x4/traits/variant_traits.hpp
@@ -4,6 +4,7 @@
 /*=============================================================================
     Copyright (c) 2001-2014 Joel de Guzman
     Copyright (c) 2025 Nana Sakisaka
+    Copyright (c) 2026 The Iris Project Contributors
 
     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)
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 3d351e5f2..52344c86a 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -1,4 +1,5 @@
 # Copyright 2025-2026 Nana Sakisaka
+# Copyright 2026 The Iris Project Contributors
 #
 # Distributed under the Boost Software License, Version 1.0.
 # https://www.boost.org/LICENSE_1_0.txt
diff --git a/test/x4/CMakeLists.txt b/test/x4/CMakeLists.txt
index bc4f18fe6..80fd923a8 100644
--- a/test/x4/CMakeLists.txt
+++ b/test/x4/CMakeLists.txt
@@ -1,4 +1,5 @@
 # Copyright 2025-2026 Nana Sakisaka
+# Copyright 2026 The Iris Project Contributors
 #
 # Distributed under the Boost Software License, Version 1.0.
 # https://www.boost.org/LICENSE_1_0.txt