diff --git a/docs/redirects.json b/docs/redirects.json
index 762e1b6..c3402a9 100644
--- a/docs/redirects.json
+++ b/docs/redirects.json
@@ -77,6 +77,15 @@
   "blocks-authelia-options-shb.authelia.enable": [
     "blocks-authelia.html#blocks-authelia-options-shb.authelia.enable"
   ],
+  "blocks-authelia-options-shb.authelia.extraDefinitions": [
+    "blocks-authelia.html#blocks-authelia-options-shb.authelia.extraDefinitions"
+  ],
+  "blocks-authelia-options-shb.authelia.extraOidcClaimsPolicies": [
+    "blocks-authelia.html#blocks-authelia-options-shb.authelia.extraOidcClaimsPolicies"
+  ],
+  "blocks-authelia-options-shb.authelia.extraOidcScopes": [
+    "blocks-authelia.html#blocks-authelia-options-shb.authelia.extraOidcScopes"
+  ],
   "blocks-authelia-options-shb.authelia.ldapHostname": [
     "blocks-authelia.html#blocks-authelia-options-shb.authelia.ldapHostname"
   ],
@@ -3041,6 +3050,9 @@
   "services-nextcloudserver-options-shb.nextcloud.apps.sso": [
     "services-nextcloud.html#services-nextcloudserver-options-shb.nextcloud.apps.sso"
   ],
+  "services-nextcloudserver-options-shb.nextcloud.apps.sso.adminGroup": [
+    "services-nextcloud.html#services-nextcloudserver-options-shb.nextcloud.apps.sso.adminGroup"
+  ],
   "services-nextcloudserver-options-shb.nextcloud.apps.sso.authorization_policy": [
     "services-nextcloud.html#services-nextcloudserver-options-shb.nextcloud.apps.sso.authorization_policy"
   ],
diff --git a/modules/blocks/authelia.nix b/modules/blocks/authelia.nix
index 6de9eef..cb8a418 100644
--- a/modules/blocks/authelia.nix
+++ b/modules/blocks/authelia.nix
@@ -140,6 +140,24 @@ in
       };
     };
 
+    extraOidcClaimsPolicies = lib.mkOption {
+      description = "Extra OIDC claims policies.";
+      type = lib.types.attrsOf lib.types.attrs;
+      default = {};
+    };
+
+    extraOidcScopes = lib.mkOption {
+      description = "Extra OIDC scopes.";
+      type = lib.types.attrsOf lib.types.attrs;
+      default = {};
+    };
+
+    extraDefinitions = lib.mkOption {
+      description = "Extra definitions.";
+      type = lib.types.attrsOf lib.types.attrs;
+      default = {};
+    };
+
     oidcClients = lib.mkOption {
       description = "OIDC clients";
       default = [
@@ -205,13 +223,13 @@ in
 
           scopes = lib.mkOption {
             type = lib.types.listOf lib.types.str;
-            description = "Scopes to ask for";
+            description = "Scopes to ask for. See https://www.authelia.com/integration/openid-connect/openid-connect-1.0-claims";
             example = [ "openid" "profile" "email" "groups" ];
             default = [];
           };
 
           claims_policy = lib.mkOption {
-            type = lib.types.str;
+            type = lib.types.nullOr lib.types.str;
             description = ''
               Claim policy.
 
@@ -387,11 +405,6 @@ in
             user = "uid=admin,ou=people,${cfg.dcdomain}";
           };
         };
-        # This should go away at some point.
-        # https://www.authelia.com/integration/openid-connect/openid-connect-1.0-claims/#restore-functionality-prior-to-claims-parameter
-        identity_providers.oidc = {
-          claims_policies.default.id_token = [ "email" "preferred_username" "name" "groups" ];
-        };
         totp = {
           disable = "false";
           issuer = fqdnWithPort;
@@ -465,6 +478,17 @@ in
         };
 
         log.level = if cfg.debug then "debug" else "info";
+      } // {
+        identity_providers.oidc = {
+          claims_policies = {
+            # This default claim should go away at some point.
+            # https://www.authelia.com/integration/openid-connect/openid-connect-1.0-claims/#restore-functionality-prior-to-claims-parameter
+            default.id_token = [ "email" "preferred_username" "name" "groups" ];
+          } // cfg.extraOidcClaimsPolicies;
+          scopes = cfg.extraOidcScopes;
+        };
+      } // lib.optionalAttrs (cfg.extraDefinitions != {}) {
+        definitions = cfg.extraDefinitions;
       };
 
       settingsFiles = [ "/var/lib/authelia-${fqdn}/oidc_clients.yaml" ];
diff --git a/modules/services/nextcloud-server.nix b/modules/services/nextcloud-server.nix
index 1a05f24..033a7ca 100644
--- a/modules/services/nextcloud-server.nix
+++ b/modules/services/nextcloud-server.nix
@@ -414,7 +414,6 @@ in
                   };
                 };
 
-
                 userGroup = lib.mkOption {
                   type = lib.types.str;
                   description = "Group users must belong to to be able to login to Nextcloud.";
@@ -424,8 +423,8 @@ in
                 configID = lib.mkOption {
                   type = lib.types.int;
                   description = ''
-                    Multiple LDAP configs can co-exist with only one active at a time.This option
-                    sets the config ID used by Self Host Blocks.
+                    Multiple LDAP configs can co-exist with only one active at a time.
+                    This option sets the config ID used by Self Host Blocks.
                   '';
                   default = 50;
                 };
@@ -475,6 +474,12 @@ in
                   default = "one_factor";
                 };
 
+                adminGroup = lib.mkOption {
+                  type = lib.types.str;
+                  description = "Group admins must belong to to be able to login to Nextcloud.";
+                  default = "nextcloud_admin";
+                };
+
                 secret = lib.mkOption {
                   description = "OIDC shared secret.";
                   type = lib.types.submodule {
@@ -1022,7 +1027,7 @@ in
         ${occ} ldap:set-config "${cID}" 'ldapLoginFilterAttributes' \
                   'mail;objectclass'
         ${occ} ldap:set-config "${cID}" 'ldapUserDisplayName' \
-                  'displayname'
+                  'givenname'
         ${occ} ldap:set-config "${cID}" 'ldapUserFilter' \
                   '(&(objectclass=person)(memberOf=cn=${cfg'.userGroup},ou=groups,${cfg'.dcdomain}))'
         ${occ} ldap:set-config "${cID}" 'ldapUserFilterMode' \
@@ -1033,7 +1038,7 @@ in
         # Nextcloud is compatible with the one returned by a (possibly added in the future) SSO
         # provider.
         ${occ} ldap:set-config "${cID}" 'ldapExpertUsernameAttr' \
-                  'user_id'
+                  'uid'
 
         ${occ} ldap:test-config -- "${cID}"
 
@@ -1057,6 +1062,7 @@ in
           "profile"
           "email"
           "groups"
+          "nextcloud_userinfo"
         ];
     in lib.mkIf (cfg.enable && cfg.apps.sso.enable) {
       assertions = [
@@ -1070,11 +1076,9 @@ in
         }
       ];
 
-      systemd.services.nextcloud-setup.script =
-        ''
-        ${occ} app:install oidc_login || :
-        ${occ} app:enable  oidc_login
-        '';
+      services.nextcloud.extraApps = {
+        inherit (nextcloudApps) oidc_login;
+      };
 
       systemd.services.nextcloud-setup-pre = {
         wantedBy = [ "multi-user.target" ];
@@ -1096,6 +1100,12 @@ in
         secretFile = "${cfg.dataDir}/config/secretFile";
 
         # See all options at https://github.com/pulsejet/nextcloud-oidc-login
+        # Other important url/links are:
+        #   ${fqdn}/.well-known/openid-configuration
+        #   https://www.authelia.com/reference/guides/attributes/#custom-attributes
+        #   https://github.com/lldap/lldap/blob/main/example_configs/nextcloud_oidc_authelia.md
+        #   https://www.authelia.com/integration/openid-connect/nextcloud/#authelia
+        #   https://www.openidconnect.net/
         settings = {
           allow_user_to_change_display_name = false;
           lost_password_link = "disabled";
@@ -1110,12 +1120,14 @@ in
           oidc_login_logout_url = ssoFqdnWithPort;
           oidc_login_button_text = "Log in with ${cfg.apps.sso.provider}";
           oidc_login_hide_password_form = false;
-          oidc_login_use_id_token = true;
+          # Now, Authelia provides the info using the UserInfo request.
+          oidc_login_use_id_token = false;
           oidc_login_attributes = {
             id = "preferred_username";
             name = "name";
             mail = "email";
             groups = "groups";
+            is_admin = "is_nextcloud_admin";
           };
           oidc_login_default_group = "oidc";
           oidc_login_use_external_storage = false;
@@ -1136,8 +1148,7 @@ in
           # they are not already existing, Default is `false`. This creates groups for all groups
           # the user is associated with in LDAP. It's too much.
           oidc_create_groups = false;
-          # Enable use of WebDAV via OIDC bearer token.
-          oidc_login_webdav_enabled = true;
+          oidc_login_webdav_enabled = false;
           oidc_login_password_authentication = false;
           oidc_login_public_key_caching_time = 86400;
           oidc_login_min_time_between_jwks_requests = 10;
@@ -1145,19 +1156,39 @@ in
           # If true, nextcloud will download user avatars on login. This may lead to security issues
           # as the server does not control which URLs will be requested. Use with care.
           oidc_login_update_avatar = false;
+          oidc_login_code_challenge_method = "S256";
         };
       };
 
+      shb.authelia.extraDefinitions = {
+        user_attributes."is_nextcloud_admin".expression = ''type(groups) == list && "${cfg.apps.sso.adminGroup}" in groups'';
+      };
+      shb.authelia.extraOidcClaimsPolicies."nextcloud_userinfo" = {
+        custom_claims = {
+          is_nextcloud_admin = {};
+        };
+      };
+      shb.authelia.extraOidcScopes."nextcloud_userinfo" = {
+        claims = [ "is_nextcloud_admin" ];
+      };
+
       shb.authelia.oidcClients = lib.mkIf (cfg.apps.sso.provider == "Authelia") [
         {
           client_id = cfg.apps.sso.clientID;
           client_name = "Nextcloud";
           client_secret.source = cfg.apps.sso.secretForAuthelia.result.path;
+          claims_policy = "nextcloud_userinfo";
           public = false;
           authorization_policy = cfg.apps.sso.authorization_policy;
+          require_pkce = "true";
+          pkce_challenge_method = "S256";
           redirect_uris = [ "${protocol}://${fqdnWithPort}/apps/oidc_login/oidc" ];
           inherit scopes;
-          userinfo_signing_algorithm = "none";
+          response_types = [ "code" ];
+          grant_types = [ "authorization_code" ];
+          access_token_signed_response_alg = "none";
+          userinfo_signed_response_alg = "none";
+          token_endpoint_auth_method = "client_secret_basic";
         }
       ];
     })
diff --git a/modules/services/nextcloud-server/docs/default.md b/modules/services/nextcloud-server/docs/default.md
index ea1ee0c..57760e9 100644
--- a/modules/services/nextcloud-server/docs/default.md
+++ b/modules/services/nextcloud-server/docs/default.md
@@ -179,10 +179,9 @@ to do that with SOPS we use the `key` option so that both
 and `sops.secrets."nextcloud/ldapUserPassword"`
 secrets have the same content.
 
-Creating LDAP users and groups is not declarative yet,
-so go to the LDAP server at `http://ldap.example.com`,
-create the `nextcloud_user` group,
-create a user and add it to the group.
+The LDAP [user group](#services-nextcloudserver-options-shb.nextcloud.apps.ldap.userGroup) is created automatically.
+Add your user to it by going to `http://ldap.example.com`,
+create a user if needed and add it to the group.
 When that's done, go back to the Nextcloud server at
 `https://nextcloud.example.com` and login with that user.
 
@@ -190,6 +189,7 @@ Note that we cannot create an admin user from the LDAP server,
 so you need to create a normal user like above,
 login with it once so it is known to Nextcloud, then logout,
 login with the admin Nextcloud user and promote that new user to admin level.
+This limitation does not exist with the [SSO integration](#services-nextcloudserver-usage-oidc).
 
 ### With SSO Support {#services-nextcloudserver-usage-oidc}
 
@@ -231,6 +231,12 @@ to do that with SOPS we use the `key` option so that both
 and `sops.secrets."nextcloud/sso/secretForAuthelia"`
 secrets have the same content.
 
+The LDAP [user group](#services-nextcloudserver-options-shb.nextcloud.apps.ldap.userGroup) and [admin group](#services-nextcloudserver-options-shb.nextcloud.apps.sso.adminGroup) are created automatically.
+Add your user to one or both by going to `http://ldap.example.com`,
+create a user if needed and add it to the groups.
+When that's done, go back to the Nextcloud server at
+`https://nextcloud.example.com` and login with that user.
+
 Setting the `fallbackDefaultAuth` to `false` means the only way to login is through Authelia.
 If this does not work for any reason, you can let users login through Nextcloud directly by setting this option to `true`.
 
diff --git a/test/common.nix b/test/common.nix
index 5c5b374..8450fc6 100644
--- a/test/common.nix
+++ b/test/common.nix
@@ -198,6 +198,10 @@ in
       # HTTP(s) server port.
       networking.firewall.allowedTCPPorts = [ 80 443 ];
       shb.nginx.accessLog = true;
+
+      networking.hosts = {
+        "192.168.1.2" = [ config.test.fqdn ];
+      };
     };
   };
 
@@ -415,6 +419,11 @@ in
           groups = [ "user_group" "admin_group" ];
           password.result.path = pkgs.writeText "bobPassword" "BobPassword";
         };
+        # charlie = {
+        #   email = "charlie@example.com";
+        #   groups = [ ];
+        #   password.result.path = pkgs.writeText "charliePassword" "CharliePassword";
+        # };
       };
 
       ensureGroups = {
@@ -430,7 +439,7 @@ in
     ];
 
     networking.hosts = {
-      "127.0.0.1" = [ "auth.${config.test.domain}" ];
+      "127.0.0.1" = [ "${config.shb.authelia.subdomain}.${config.shb.authelia.domain}" ];
     };
 
     shb.authelia = {
diff --git a/test/services/nextcloud.nix b/test/services/nextcloud.nix
index dad3a1f..2c46aeb 100644
--- a/test/services/nextcloud.nix
+++ b/test/services/nextcloud.nix
@@ -151,6 +151,91 @@ let
     };
   };
 
+  clientLdapLogin = { config, ... }: {
+    imports = [
+      testLib.baseModule
+      testLib.clientLoginModule
+    ];
+    virtualisation.memorySize = 4096;
+
+    test = {
+      subdomain = "n";
+    };
+
+    test.login = {
+      startUrl = "http://${config.test.fqdn}";
+      usernameFieldLabelRegex = "Account name";
+      passwordFieldLabelRegex = "^ *[Pp]assword";
+      loginButtonNameRegex = "[Ll]og [Ii]n";
+      testLoginWith = [
+        { username = "alice"; password = "AlicePassword"; nextPageExpect = [
+            "expect(page.get_by_text('Wrong login or password')).not_to_be_visible()"
+            "expect(page.get_by_role('button', name=re.compile('[Ll]og [Ii]n'))).not_to_be_visible()"
+            "expect(page).to_have_title(re.compile('Dashboard'))"
+          ]; }
+        { username = "alice"; password = "NotAlicePassword"; nextPageExpect = [
+            "expect(page.get_by_text('Wrong login or password')).to_be_visible()"
+          ]; }
+        { username = "bob"; password = "BobPassword"; nextPageExpect = [
+            "expect(page.get_by_text('Wrong login or password')).not_to_be_visible()"
+            "expect(page.get_by_role('button', name=re.compile('[Ll]og [Ii]n'))).not_to_be_visible()"
+            "expect(page).to_have_title(re.compile('Dashboard'))"
+          ]; }
+        { username = "bob"; password = "NotBobPassword"; nextPageExpect = [
+            "expect(page.get_by_text('Wrong login or password')).to_be_visible()"
+          ]; }
+      ];
+    };
+  };
+
+  clientSsoLogin = { config, ... }: {
+    imports = [
+      testLib.baseModule
+      testLib.clientLoginModule
+    ];
+    virtualisation.memorySize = 4096;
+
+    test = {
+      subdomain = "n";
+    };
+
+    networking.hosts = {
+      "192.168.1.2" = [ "auth.example.com" ];
+    };
+
+    test.login = {
+      startUrl = "http://${config.test.fqdn}";
+      usernameFieldLabelRegex = "Username";
+      passwordFieldSelector = "get_by_label(\"Password *\")";
+      loginButtonNameRegex = "[sS]ign [iI]n";
+      testLoginWith = [
+        { username = "alice"; password = "AlicePassword"; nextPageExpect = [
+            "page.get_by_role('button', name=re.compile('Accept')).click()"
+            "expect(page).to_have_title(re.compile('Dashboard'))"
+            "page.goto('https://${config.test.fqdn}/settings/admin')"
+            "expect(page.get_by_text('Access forbidden')).to_be_visible()"
+          ]; }
+        { username = "alice"; password = "NotAlicePassword"; nextPageExpect = [
+            "expect(page.get_by_text('Incorrect username or password')).to_be_visible()"
+          ]; }
+        { username = "bob"; password = "BobPassword"; nextPageExpect = [
+            "page.get_by_role('button', name=re.compile('Accept')).click()"
+            "expect(page).to_have_title(re.compile('Dashboard'))"
+            "page.goto('https://${config.test.fqdn}/settings/admin')"
+            "expect(page.get_by_text('Access forbidden')).not_to_be_visible()"
+          ]; }
+        { username = "bob"; password = "NotBobPassword"; nextPageExpect = [
+            "expect(page.get_by_text('Incorrect username or password')).to_be_visible()"
+          ]; }
+        # TODO: charlie has no groups, which makes lldap return a 'null' value instead of an empty array and Authelia does not like that.
+        # { username = "charlie"; password = "CharliePassword"; nextPageExpect = [
+        #     "page.get_by_role('button', name=re.compile('Accept')).click()"
+        #     "expect(page).to_have_title(re.compile('Dashboard'))"
+        #   ]; }
+      ];
+    };
+  };
+
   https = { config, ...}: {
     shb.nextcloud = {
       ssl = config.shb.certs.certs.selfsigned.n;
@@ -168,7 +253,7 @@ let
         dcdomain = config.shb.lldap.dcdomain;
         adminName = "admin";
         adminPassword.result = config.shb.hardcodedsecret.nextcloudLdapUserPassword.result;
-        userGroup = "nextcloud_user";
+        userGroup = "user_group";
       };
     };
     shb.hardcodedsecret.nextcloudLdapUserPassword = {
@@ -184,7 +269,7 @@ let
           enable = true;
           endpoint = "https://${config.shb.authelia.subdomain}.${config.shb.authelia.domain}";
           clientID = "nextcloud";
-          # adminUserGroup = "nextcloud_admin";
+          adminGroup = "admin_group";
 
           secret.result = config.shb.hardcodedsecret.oidcSecret.result;
           secretForAuthelia.result = config.shb.hardcodedsecret.oidcAutheliaSecret.result;
@@ -192,6 +277,10 @@ let
           fallbackDefaultAuth = false;
         };
       };
+      # Needed because OIDC somehow does not like self-signed certificates
+      # which we do use in tests.
+      # See https://github.com/pulsejet/nextcloud-oidc-login/issues/267
+      services.nextcloud.settings.oidc_login_tls_verify = lib.mkForce false;
 
       shb.hardcodedsecret.oidcSecret = {
         request = config.shb.nextcloud.apps.sso.secret.request;
@@ -436,13 +525,19 @@ in
       ];
     };
   
-    nodes.client = {};
+    nodes.client = {
+      imports = [
+        clientLdapLogin
+      ];
+    };
   
     testScript = commonTestScript.access;
   };
 
   sso = pkgs.testers.runNixOSTest {
     name = "nextcloud_sso";
+
+    interactive.sshBackdoor.enable = true;
   
     nodes.server = { config, ... }: {
       imports = [
@@ -453,10 +548,24 @@ in
         ldap
         (testLib.sso config.shb.certs.certs.selfsigned.n)
         sso
+        ({ config, ... }: {
+          networking.hosts = {
+            "127.0.0.1" = [ config.test.fqdn ];
+          };
+        })
       ];
     };
   
-    nodes.client = {};
+    nodes.client = {
+      imports = [
+        clientSsoLogin
+        ({ config, ... }: {
+          networking.hosts = {
+            "192.168.1.2" = [ config.test.fqdn ];
+          };
+        })
+      ];
+    };
   
     testScript = commonTestScript.access;
   };