diff --git a/internal/folding/whitespace.go b/internal/folding/whitespace.go
index ffd8530..d415439 100644
--- a/internal/folding/whitespace.go
+++ b/internal/folding/whitespace.go
@@ -1,3 +1,17 @@
+// Copyright 2025 Ian Lewis
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package folding
 
 import (
diff --git a/internal/testutil/syn.go b/internal/testutil/syn.go
index c81c44c..08c0263 100644
--- a/internal/testutil/syn.go
+++ b/internal/testutil/syn.go
@@ -1,4 +1,4 @@
-// Copyright 2024 Ian Lewis
+// Copyright 2025 Ian Lewis
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
diff --git a/syn/syn.go b/syn/syn.go
index 02f599f..9623146 100644
--- a/syn/syn.go
+++ b/syn/syn.go
@@ -1,4 +1,4 @@
-// Copyright 2024 Ian Lewis
+// Copyright 2025 Ian Lewis
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
diff --git a/syn/syn_test.go b/syn/syn_test.go
index 3024378..056ae4e 100644
--- a/syn/syn_test.go
+++ b/syn/syn_test.go
@@ -1,3 +1,17 @@
+// Copyright 2025 Ian Lewis
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package syn_test
 
 import (