document compatibility mode for oidc logout endpoint suppression

upgrading/topics/keycloak/changes-18_0_0.adoc

@@ -68,7 +68,7 @@ endif::[]
 
 With this configuration, you can still use the format with the `redirect_uri` parameter. Note the confirmation screen will be needed if the `id_token_hint` is omitted.
 
-WARNING: The backwards compatibility switch will be removed in some future version - probably Keycloak 21. You are encouraged to update your clients as soon as possible
+WARNING: The backwards compatibility switch will be removed in some future version - probably Keycloak 23. You are encouraged to update your clients as soon as possible
 as described above rather than rely on this switch.
 
 = Removal of the `upload-scripts` feature

upgrading/topics/keycloak/changes-19_0_2.adoc

@@ -0,0 +1,31 @@
+= OpenID Connect Logout Prompt
+At Keycloak 18.0.0, the logout is now compatible with the new OIDC specification, which changed the handling for the url parameters. However, to also remain compatible with earlier versions, a compatibility flag is introduced. See the link:{upgradingguide_link}#openid-connect-logout[{upgradingguide_name}] for further information for the backwards compatibility option, which allows your application to still use the old format for the url parameters.
+
+While the url parameters can now be configured to be compatible, there was still one incompatibility with keycloak 17 and earlier releases. If the user does not provide an valid `idTokenHint`, a logout prompt appears instead of a successful logout redirect. Therefore, a new compatibility flag `suppress-logout-confirmation-screen` is introduced to suppress the logout screen.
+
+ifeval::["{kc_dist}" == "quarkus"]
+You can enable this parameter when you start the server by entering the following command:
+
+```
+bin/kc.[sh|bat] --spi-login-protocol-openid-connect-suppress-logout-confirmation-screen=true start
+```
+endif::[]
+
+ifeval::["{kc_dist}" == "wildfly"]
+You can enable this parameter by including the following configuration in the `standalone-*.xml` file
+
+[source,bash,subs=+attributes]
+----
+<spi name="login-protocol">
+    <provider name="openid-connect" enabled="true">
+        <properties>
+            <property name="suppress-logout-confirmation-screen" value="true"/>
+        </properties>
+    </provider>
+</spi>
+----
+endif::[]
+
+With this configuration, you can still use the logout endpoint without a user prompt.
+
+WARNING: The backwards compatibility switch will be removed in some future version - probably Keycloak 23. You are encouraged to update your clients as soon as possible as described above rather than rely on this switch.

upgrading/topics/keycloak/changes.adoc

@@ -1,5 +1,9 @@
 == Migration Changes
 
+=== Migrating to 19.0.2
+
+include::changes-19_0_2.adoc[leveloffset=3]
+
 === Migrating to 19.0.0
 
 include::changes-19_0_0.adoc[leveloffset=3]