diff --git a/src/Benchmarks/ByIgnoringBenchmarks.cs b/src/Benchmarks/ByIgnoringBenchmarks.cs
index 59b3408..504ef69 100644
--- a/src/Benchmarks/ByIgnoringBenchmarks.cs
+++ b/src/Benchmarks/ByIgnoringBenchmarks.cs
@@ -1,3 +1,17 @@
+// Copyright 2017 Serilog Contributors
+//
+// 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.
+
 using BenchmarkDotNet.Attributes;
 using Destructurama;
 using Serilog;
diff --git a/src/Benchmarks/DelegatingSink.cs b/src/Benchmarks/DelegatingSink.cs
index 959666f..a1b5231 100644
--- a/src/Benchmarks/DelegatingSink.cs
+++ b/src/Benchmarks/DelegatingSink.cs
@@ -1,3 +1,17 @@
+// Copyright 2017 Serilog Contributors
+//
+// 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.
+
 using Serilog.Core;
 using Serilog.Events;
 
diff --git a/src/Destructurama.ByIgnoring.Tests/Approval/ApiApprovalTests.cs b/src/Destructurama.ByIgnoring.Tests/Approval/ApiApprovalTests.cs
index b87204e..03b4006 100644
--- a/src/Destructurama.ByIgnoring.Tests/Approval/ApiApprovalTests.cs
+++ b/src/Destructurama.ByIgnoring.Tests/Approval/ApiApprovalTests.cs
@@ -1,3 +1,17 @@
+// Copyright 2017 Serilog Contributors
+//
+// 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.
+
 using NUnit.Framework;
 using PublicApiGenerator;
 using Shouldly;
diff --git a/src/Destructurama.ByIgnoring.Tests/Support/DelegatingSink.cs b/src/Destructurama.ByIgnoring.Tests/Support/DelegatingSink.cs
index fb50c05..d551b29 100644
--- a/src/Destructurama.ByIgnoring.Tests/Support/DelegatingSink.cs
+++ b/src/Destructurama.ByIgnoring.Tests/Support/DelegatingSink.cs
@@ -1,3 +1,17 @@
+// Copyright 2017 Serilog Contributors
+//
+// 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.
+
 using Serilog.Core;
 using Serilog.Events;
 
diff --git a/src/Destructurama.ByIgnoring.Tests/Support/Extensions.cs b/src/Destructurama.ByIgnoring.Tests/Support/Extensions.cs
index dcb9151..824d1b1 100644
--- a/src/Destructurama.ByIgnoring.Tests/Support/Extensions.cs
+++ b/src/Destructurama.ByIgnoring.Tests/Support/Extensions.cs
@@ -1,3 +1,17 @@
+// Copyright 2017 Serilog Contributors
+//
+// 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.
+
 using Serilog.Events;
 
 namespace Destructurama.ByIgnoring.Tests.Support;
diff --git a/src/Destructurama.ByIgnoring.Tests/Support/FluentAssertionExtensions.cs b/src/Destructurama.ByIgnoring.Tests/Support/FluentAssertionExtensions.cs
index 8caee6d..ee7de9b 100644
--- a/src/Destructurama.ByIgnoring.Tests/Support/FluentAssertionExtensions.cs
+++ b/src/Destructurama.ByIgnoring.Tests/Support/FluentAssertionExtensions.cs
@@ -1,6 +1,16 @@
-// (C) Copyright 2023 Nullable, Inc. All rights reserved.
-// This file is part of Nullable's product Aware and cannot be copied and/or
-// distributed without the express permission of Nullable, Inc.
+// Copyright 2017 Serilog Contributors
+//
+// 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.
 
 using FluentAssertions;
 using FluentAssertions.Equivalency;