diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 1919de7..cb2637b 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -1,9 +1,7 @@
-# Copyright 2019-2021 by Vegard IT GmbH, Germany, https://vegardit.com
+# SPDX-FileCopyrightText: © Vegard IT GmbH (https://vegardit.com)
+# SPDX-FileContributor: Sebastian Thomschke
 # SPDX-License-Identifier: Apache-2.0
-#
-# Author: Sebastian Thomschke, Vegard IT GmbH
-#
-# https://github.com/vegardit/docker-openldap
+# SPDX-ArtifactOfProjectHomePage: https://github.com/vegardit/docker-openldap
 #
 # https://docs.github.com/en/free-pro-team@latest/actions/reference/workflow-syntax-for-github-actions
 name: Build
diff --git a/build-image.sh b/build-image.sh
index eeb7f25..ad6823c 100644
--- a/build-image.sh
+++ b/build-image.sh
@@ -1,11 +1,9 @@
 #!/usr/bin/env bash
 #
-# Copyright 2019-2021 by Vegard IT GmbH, Germany, https://vegardit.com
+# SPDX-FileCopyrightText: © Vegard IT GmbH (https://vegardit.com)
+# SPDX-FileContributor: Sebastian Thomschke
 # SPDX-License-Identifier: Apache-2.0
-#
-# Author: Sebastian Thomschke, Vegard IT GmbH
-#
-# https://github.com/vegardit/docker-openldap
+# SPDX-ArtifactOfProjectHomePage: https://github.com/vegardit/docker-openldap
 
 shared_lib="$(dirname $0)/.shared"
 [ -e "$shared_lib" ] || curl -sSf https://raw.githubusercontent.com/vegardit/docker-shared/v1/download.sh?_=$(date +%s) | bash -s v1 "$shared_lib" || exit 1
diff --git a/image/Dockerfile b/image/Dockerfile
index 9d7f21f..1901e31 100644
--- a/image/Dockerfile
+++ b/image/Dockerfile
@@ -1,11 +1,12 @@
-#syntax=docker/dockerfile:1.2
-# Copyright 2019-2021 by Vegard IT GmbH, Germany, https://vegardit.com
+#syntax=docker/dockerfile:1.4
+# see https://github.com/moby/buildkit/blob/master/frontend/dockerfile/docs/syntax.md#user-content-syntax
+# see https://docs.docker.com/build/dockerfile/frontend/
+# see https://docs.docker.com/engine/reference/builder/#syntax
+#
+# SPDX-FileCopyrightText: © Vegard IT GmbH (https://vegardit.com)
+# SPDX-FileContributor: Sebastian Thomschke
 # SPDX-License-Identifier: Apache-2.0
-#
-# Author: Sebastian Thomschke, Vegard IT GmbH
-#
-# https://github.com/vegardit/docker-openldap
-#
+# SPDX-ArtifactOfProjectHomePage: https://github.com/vegardit/docker-openldap
 
 # https://hub.docker.com/_/debian?tab=tags&name=bullseye-slim
 ARG BASE_IMAGE=debian:bullseye-slim
diff --git a/image/run.sh b/image/run.sh
index 3cd7638..191f05a 100644
--- a/image/run.sh
+++ b/image/run.sh
@@ -1,12 +1,9 @@
 #!/usr/bin/env bash
 #
-# Copyright 2019-2020 by Vegard IT GmbH, Germany, https://vegardit.com
+# SPDX-FileCopyrightText: © Vegard IT GmbH (https://vegardit.com)
+# SPDX-FileContributor: Sebastian Thomschke
 # SPDX-License-Identifier: Apache-2.0
-#
-# Author: Sebastian Thomschke, Vegard IT GmbH
-#
-# https://github.com/vegardit/docker-openldap
-#
+# SPDX-ArtifactOfProjectHomePage: https://github.com/vegardit/docker-openldap
 
 source /opt/bash-init.sh