diff --git a/lib/types/thread-types.js b/lib/types/thread-types.js
--- a/lib/types/thread-types.js
+++ b/lib/types/thread-types.js
@@ -33,6 +33,7 @@
 import { type ThreadType, threadTypeValidator } from './thread-types-enum.js';
 import type { ClientUpdateInfo, ServerUpdateInfo } from './update-types.js';
 import type { UserInfo, UserInfos } from './user-types.js';
+import type { SpecialRole } from '../permissions/special-roles.js';
 import { type ThreadEntity } from '../utils/entity-text.js';
 import { tID, tShape } from '../utils/validation-utils.js';
 
@@ -64,6 +65,14 @@
     isDefault: t.Boolean,
   });
 
+export type ServerClientLegacyRoleInfo = {
+  +id: string,
+  +name: string,
+  +permissions: ThreadRolePermissionsBlob,
+  +isDefault: boolean,
+  +specialRole: ?SpecialRole,
+};
+
 export type LegacyThreadCurrentUserInfo = {
   +role: ?string,
   +permissions: ThreadPermissionsInfo,