diff --git a/demos/gtk-demo/meson.build b/demos/gtk-demo/meson.build
index abfe033df4..24e4abe05d 100644
--- a/demos/gtk-demo/meson.build
+++ b/demos/gtk-demo/meson.build
@@ -205,4 +205,9 @@ install_data('org.gtk.Demo4.gschema.xml', install_dir: gtk_schemasdir)
 gnome.compile_schemas()
 
 # appdata
-install_data('org.gtk.Demo4.appdata.xml', install_dir: gtk_appdatadir)
+configure_file(
+  input: 'org.gtk.Demo4.appdata.xml.in',
+  output: 'org.gtk.Demo4.appdata.xml',
+  configuration: appdata_config,
+  install_dir: gtk_appdatadir
+)
diff --git a/demos/gtk-demo/org.gtk.Demo4.appdata.xml b/demos/gtk-demo/org.gtk.Demo4.appdata.xml.in
similarity index 81%
rename from demos/gtk-demo/org.gtk.Demo4.appdata.xml
rename to demos/gtk-demo/org.gtk.Demo4.appdata.xml.in
index f102eb7eaa..7aa94b8bf8 100644
--- a/demos/gtk-demo/org.gtk.Demo4.appdata.xml
+++ b/demos/gtk-demo/org.gtk.Demo4.appdata.xml.in
@@ -31,14 +31,9 @@
   <update_contact>matthias.clasen_at_gmail.com</update_contact>
   <developer_name>Matthias Clasen and others</developer_name>
   <releases>
-    <release version="3.99.0" date="2020-07-30">
+    <release version="@BUILD_VERSION@" date="@BUILD_DATE@">
       <description>
-        <p>A new developers snapshot towards GTK 4.0.</p>
-      </description>
-    </release>
-    <release version="3.94.0" date="2018-06-25">
-      <description>
-        <p>A new developers snapshot towards GTK 4.0.</p>
+        <p>A new build of GTK.</p>
       </description>
     </release>
   </releases>
diff --git a/demos/icon-browser/meson.build b/demos/icon-browser/meson.build
index 3922811f92..9c7ddb99de 100644
--- a/demos/icon-browser/meson.build
+++ b/demos/icon-browser/meson.build
@@ -32,5 +32,10 @@ endforeach
 install_data('org.gtk.IconBrowser4.desktop', install_dir: gtk_applicationsdir)
 
 # appdata
-install_data('org.gtk.IconBrowser4.appdata.xml', install_dir: gtk_appdatadir)
+configure_file(
+  input: 'org.gtk.IconBrowser4.appdata.xml.in',
+  output: 'org.gtk.IconBrowser4.appdata.xml',
+  configuration: appdata_config,
+  install_dir: gtk_appdatadir
+)
 
diff --git a/demos/icon-browser/org.gtk.IconBrowser4.appdata.xml b/demos/icon-browser/org.gtk.IconBrowser4.appdata.xml.in
similarity index 81%
rename from demos/icon-browser/org.gtk.IconBrowser4.appdata.xml
rename to demos/icon-browser/org.gtk.IconBrowser4.appdata.xml.in
index 8ae3f259f6..d5c8bac706 100644
--- a/demos/icon-browser/org.gtk.IconBrowser4.appdata.xml
+++ b/demos/icon-browser/org.gtk.IconBrowser4.appdata.xml.in
@@ -30,14 +30,9 @@
   <update_contact>matthias.clasen_at_gmail.com</update_contact>
   <developer_name>Matthias Clasen and others</developer_name>
   <releases>
-    <release version="3.99.0" date="2020-07-30">
+    <release version="@BUILD_VERSION@" date="@BUILD_DATE@">
       <description>
-        <p>A new developers snapshot towards GTK 4.0.</p>
-      </description>
-    </release>
-    <release version="3.94.0" date="2018-06-25">
-      <description>
-        <p>A new developers snapshot towards GTK 4.0.</p>
+        <p>A new build of GTK.</p>
       </description>
     </release>
   </releases>
diff --git a/demos/meson.build b/demos/meson.build
index 5b68828eef..de720925f6 100644
--- a/demos/meson.build
+++ b/demos/meson.build
@@ -11,6 +11,21 @@ demo_conf_h = declare_dependency(
   )
 )
 
+# appdata
+today = 'unknown'
+date = find_program('date',
+         required: false)
+if date.found()
+  r = run_command(date, '-I')
+  if r.returncode() == 0
+    today = r.stdout().strip()
+  endif
+endif
+
+appdata_config = configuration_data()
+appdata_config.set('BUILD_VERSION', meson.project_version())
+appdata_config.set('BUILD_DATE', today)
+
 subdir('constraint-editor')
 subdir('gtk-demo')
 subdir('icon-browser')
diff --git a/demos/widget-factory/meson.build b/demos/widget-factory/meson.build
index e248963e24..1cebd4adc5 100644
--- a/demos/widget-factory/meson.build
+++ b/demos/widget-factory/meson.build
@@ -26,4 +26,9 @@ foreach size: ['scalable', 'symbolic']
 endforeach
 
 # appdata
-install_data('org.gtk.WidgetFactory4.appdata.xml', install_dir: gtk_appdatadir)
+configure_file(
+  input: 'org.gtk.WidgetFactory4.appdata.xml.in',
+  output: 'org.gtk.WidgetFactory4.appdata.xml',
+  configuration: appdata_config,
+  install_dir: gtk_appdatadir
+)
diff --git a/demos/widget-factory/org.gtk.WidgetFactory4.appdata.xml b/demos/widget-factory/org.gtk.WidgetFactory4.appdata.xml.in
similarity index 82%
rename from demos/widget-factory/org.gtk.WidgetFactory4.appdata.xml
rename to demos/widget-factory/org.gtk.WidgetFactory4.appdata.xml.in
index b3e9889137..60e30a7e6b 100644
--- a/demos/widget-factory/org.gtk.WidgetFactory4.appdata.xml
+++ b/demos/widget-factory/org.gtk.WidgetFactory4.appdata.xml.in
@@ -32,14 +32,9 @@
   <update_contact>matthias.clasen_at_gmail.com</update_contact>
   <developer_name>Matthias Clasen and others</developer_name>
   <releases>
-    <release version="3.99.0" date="2020-07-30">
+    <release version="@BUILD_VERSION@" date="@BUILD_DATE@">
       <description>
-        <p>A new developers snapshot towards GTK 4.0.</p>
-      </description>
-    </release>
-    <release version="3.94.0" date="2018-06-25">
-      <description>
-        <p>A new developers snapshot towards GTK 4.0.</p>
+        <p>A new build of GTK.</p>
       </description>
     </release>
   </releases>