diff --git a/canaille/conf/oauth-authorization-server.sample.json b/canaille/conf/oauth-authorization-server.sample.json
index 02dea0cb..07c162a7 100644
--- a/canaille/conf/oauth-authorization-server.sample.json
+++ b/canaille/conf/oauth-authorization-server.sample.json
@@ -27,5 +27,7 @@
   "service_documentation":
     "https://auth.mydomain.tld/documentation.html",
   "ui_locales_supported":
-    ["en-US", "en-GB", "en-CA", "fr-FR", "fr-CA"]
+    ["en-US", "en-GB", "en-CA", "fr-FR", "fr-CA"],
+  "code_challenge_methods_supported":
+    ["plain", "S256"]
 }
diff --git a/canaille/conf/openid-configuration.sample.json b/canaille/conf/openid-configuration.sample.json
index 6f57f7f6..29e00237 100644
--- a/canaille/conf/openid-configuration.sample.json
+++ b/canaille/conf/openid-configuration.sample.json
@@ -62,5 +62,7 @@
   "service_documentation":
     "https://auth.mydomain.tld/oauth/service_documentation.html",
   "ui_locales_supported":
-    ["en-US", "en-GB", "en-CA", "fr-FR", "fr-CA"]
+    ["en-US", "en-GB", "en-CA", "fr-FR", "fr-CA"],
+  "code_challenge_methods_supported":
+    ["plain", "S256"]
 }
diff --git a/demo/conf-docker/oauth-authorization-server.json b/demo/conf-docker/oauth-authorization-server.json
index 0a812209..0c27dda0 100644
--- a/demo/conf-docker/oauth-authorization-server.json
+++ b/demo/conf-docker/oauth-authorization-server.json
@@ -27,5 +27,7 @@
   "service_documentation":
     "http://localhost:5000/documentation.html",
   "ui_locales_supported":
-    ["en-US", "en-GB", "en-CA", "fr-FR", "fr-CA"]
+    ["en-US", "en-GB", "en-CA", "fr-FR", "fr-CA"],
+  "code_challenge_methods_supported":
+    ["plain", "S256"]
 }
diff --git a/demo/conf-docker/openid-configuration.json b/demo/conf-docker/openid-configuration.json
index 5b1d73e6..5e77ad33 100644
--- a/demo/conf-docker/openid-configuration.json
+++ b/demo/conf-docker/openid-configuration.json
@@ -62,5 +62,7 @@
   "service_documentation":
     "http://localhost:5000/oauth/service_documentation.html",
   "ui_locales_supported":
-    ["en-US", "en-GB", "en-CA", "fr-FR", "fr-CA"]
+    ["en-US", "en-GB", "en-CA", "fr-FR", "fr-CA"],
+  "code_challenge_methods_supported":
+    ["plain", "S256"]
 }
diff --git a/demo/conf/oauth-authorization-server.json b/demo/conf/oauth-authorization-server.json
index 0a812209..0c27dda0 100644
--- a/demo/conf/oauth-authorization-server.json
+++ b/demo/conf/oauth-authorization-server.json
@@ -27,5 +27,7 @@
   "service_documentation":
     "http://localhost:5000/documentation.html",
   "ui_locales_supported":
-    ["en-US", "en-GB", "en-CA", "fr-FR", "fr-CA"]
+    ["en-US", "en-GB", "en-CA", "fr-FR", "fr-CA"],
+  "code_challenge_methods_supported":
+    ["plain", "S256"]
 }
diff --git a/demo/conf/openid-configuration.json b/demo/conf/openid-configuration.json
index b767f123..2a8022f5 100644
--- a/demo/conf/openid-configuration.json
+++ b/demo/conf/openid-configuration.json
@@ -62,5 +62,7 @@
   "service_documentation":
     "http://localhost:5000/oauth/service_documentation.html",
   "ui_locales_supported":
-    ["en-US", "en-GB", "en-CA", "fr-FR", "fr-CA"]
+    ["en-US", "en-GB", "en-CA", "fr-FR", "fr-CA"],
+  "code_challenge_methods_supported":
+    ["plain", "S256"]
 }