diff --git a/.gitignore b/.gitignore
index 18c1bf1f26a93131b9a7c6df694d7a9ca756affd..3d28c0567eef8d0223d133d3e33777f306475882 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,5 @@
 # SPDX-FileCopyrightText: 2012-2017 Bruce Cowan <bruce@bcowan.me.uk>
-# SPDX-License-Identifier: CC0-1.0
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
 
 .flatpak*
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 9c8e4a75a6f19d0ed449021bf2f4ac9bb9181789..bb2150f06c48a003f67ec509c797cfa584d012d9 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -1,6 +1,6 @@
 # SPDX-FileCopyrightText: 2018-2022 Bruce Cowan <bruce@bcowan.me.uk>
 #
-# SPDX-License-Identifier: CC0-1.0
+# SPDX-License-Identifier: GPL-3.0-or-later
 flatpak:
   image: alpine:latest
   stage: build
diff --git a/LICENSES/CC0-1.0.txt b/LICENSES/CC0-1.0.txt
deleted file mode 100644
index a343ccd4335f66ace3f9a83dfff02212a84ef4f2..0000000000000000000000000000000000000000
--- a/LICENSES/CC0-1.0.txt
+++ /dev/null
@@ -1,119 +0,0 @@
-Creative Commons Legal Code
-
-CC0 1.0 Universal CREATIVE COMMONS CORPORATION IS NOT A LAW FIRM AND DOES
-NOT PROVIDE LEGAL SERVICES. DISTRIBUTION OF THIS DOCUMENT DOES NOT CREATE
-AN ATTORNEY-CLIENT RELATIONSHIP. CREATIVE COMMONS PROVIDES THIS INFORMATION
-ON AN "AS-IS" BASIS. CREATIVE COMMONS MAKES NO WARRANTIES REGARDING THE USE
-OF THIS DOCUMENT OR THE INFORMATION OR WORKS PROVIDED HEREUNDER, AND DISCLAIMS
-LIABILITY FOR DAMAGES RESULTING FROM THE USE OF THIS DOCUMENT OR THE INFORMATION
-OR WORKS PROVIDED HEREUNDER.
-
-Statement of Purpose
-
-The laws of most jurisdictions throughout the world automatically confer exclusive
-Copyright and Related Rights (defined below) upon the creator and subsequent
-owner(s) (each and all, an "owner") of an original work of authorship and/or
-a database (each, a "Work").
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-Certain owners wish to permanently relinquish those rights to a Work for the
-purpose of contributing to a commons of creative, cultural and scientific
-works ("Commons") that the public can reliably and without fear of later claims
-of infringement build upon, modify, incorporate in other works, reuse and
-redistribute as freely as possible in any form whatsoever and for any purposes,
-including without limitation commercial purposes. These owners may contribute
-to the Commons to promote the ideal of a free culture and the further production
-of creative, cultural and scientific works, or to gain reputation or greater
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-For these and/or other purposes and motivations, and without any expectation
-of additional consideration or compensation, the person associating CC0 with
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-1. Copyright and Related Rights. A Work made available under CC0 may be protected
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-vi. database rights (such as those arising under Directive 96/9/EC of the
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-vii. other similar, equivalent or corresponding rights throughout the world
-based on applicable law or treaty, and any national implementations thereof.
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-applicable law, Affirmer hereby overtly, fully, permanently, irrevocably and
-unconditionally waives, abandons, and surrenders all of Affirmer's Copyright
-and Related Rights and associated claims and causes of action, whether now
-known or unknown (including existing as well as future claims and causes of
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-for any purpose whatsoever, including without limitation commercial, advertising
-or promotional purposes (the "Waiver"). Affirmer makes the Waiver for the
-benefit of each member of the public at large and to the detriment of Affirmer's
-heirs and successors, fully intending that such Waiver shall not be subject
-to revocation, rescission, cancellation, termination, or any other legal or
-equitable action to disrupt the quiet enjoyment of the Work by the public
-as contemplated by Affirmer's express Statement of Purpose.
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-3. Public License Fallback. Should any part of the Waiver for any reason be
-judged legally invalid or ineffective under applicable law, then the Waiver
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-express Statement of Purpose. In addition, to the extent the Waiver is so
-judged Affirmer hereby grants to each affected person a royalty-free, non
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-future medium and for any number of copies, and (iv) for any purpose whatsoever,
-including without limitation commercial, advertising or promotional purposes
-(the "License"). The License shall be deemed effective as of the date CC0
-was applied by Affirmer to the Work. Should any part of the License for any
-reason be judged legally invalid or ineffective under applicable law, such
-partial invalidity or ineffectiveness shall not invalidate the remainder of
-the License, and in such case Affirmer hereby affirms that he or she will
-not (i) exercise any of his or her remaining Copyright and Related Rights
-in the Work or (ii) assert any associated claims and causes of action with
-respect to the Work, in either case contrary to Affirmer's express Statement
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-including without limitation warranties of title, merchantability, fitness
-for a particular purpose, non infringement, or the absence of latent or other
-defects, accuracy, or the present or absence of errors, whether or not discoverable,
-all to the greatest extent permissible under applicable law.
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-use of the Work.
diff --git a/build-aux/uk.me.bcowan.Rugby.yml b/build-aux/uk.me.bcowan.Rugby.yml
index 016f8db44e92fc95be16def736f307024d6f1d4c..d072d40862b55e3532b8ab974a8b3cc08a61c791 100644
--- a/build-aux/uk.me.bcowan.Rugby.yml
+++ b/build-aux/uk.me.bcowan.Rugby.yml
@@ -1,6 +1,6 @@
 # SPDX-FileCopyrightText: 2018-2022 Bruce Cowan <bruce@bcowan.me.uk>
 #
-# SPDX-License-Identifier: CC0-1.0
+# SPDX-License-Identifier: GPL-3.0-or-later
 
 app-id: uk.me.bcowan.Rugby
 runtime: org.gnome.Platform
diff --git a/data/meson.build b/data/meson.build
index 0c3a86c7d77f8f0383a72b487e887bb6d221e88a..9dc5c0abc3f70c0b8eaaa82f170ddd8f2631dc2a 100644
--- a/data/meson.build
+++ b/data/meson.build
@@ -1,6 +1,6 @@
-# SPDX-FileCopyrightText: 2016-2021 Bruce Cowan <bruce@bcowan.me.uk>
+# SPDX-FileCopyrightText: 2016-2022 Bruce Cowan <bruce@bcowan.me.uk>
 #
-# SPDX-License-Identifier: CC0-1.0
+# SPDX-License-Identifier: GPL-3.0-or-later
 
 resources = gnome.compile_resources('gen-resources',
                                     'rugby.gresource.xml',
diff --git a/data/uk.me.bcowan.Rugby.desktop b/data/uk.me.bcowan.Rugby.desktop
index db96ee0e20cafb398d0eebc9c3d9ea70fcdf2b6f..679b1e4d88a1e1057a7cb8b1edb35cc385b1443e 100644
--- a/data/uk.me.bcowan.Rugby.desktop
+++ b/data/uk.me.bcowan.Rugby.desktop
@@ -1,6 +1,6 @@
 # SPDX-FileCopyrightText: 2020-2021 Bruce Cowan <bruce@bcowan.me.uk>
 #
-# SPDX-License-Identifier: CC0-1.0
+# SPDX-License-Identifier: GPL-3.0-or-later
 
 [Desktop Entry]
 Name=Rugby
diff --git a/meson.build b/meson.build
index 855da3e41c57d2544a4bfca7bc53a4013588838b..8b553873efd6f1b6521f90cfd801a36e5811ebd5 100644
--- a/meson.build
+++ b/meson.build
@@ -1,6 +1,6 @@
 # SPDX-FileCopyrightText: 2016-2022 Bruce Cowan <bruce@bcowan.me.uk>
 #
-# SPDX-License-Identifier: CC0-1.0
+# SPDX-License-Identifier: GPL-3.0-or-later
 
 project('rugby', 'c',
   version: '0.3.0',
diff --git a/src/meson.build b/src/meson.build
index c280d96d9e5bb7869fe7c6108a627f1aed97bfc4..679d975ce74d65e9a7a23b7a1f189e5fdaad7965 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -1,6 +1,6 @@
 # SPDX-FileCopyrightText: 2016-2022 Bruce Cowan <bruce@bcowan.me.uk>
 #
-# SPDX-License-Identifier: CC0-1.0
+# SPDX-License-Identifier: GPL-3.0-or-later
 sources = [
     'main.c',
     'rugby-app-window.c',