diff --git a/lib/server.ts b/lib/server.ts
index 1651a2ed..160b2d88 100644
--- a/lib/server.ts
+++ b/lib/server.ts
@@ -320,7 +320,7 @@ export abstract class BaseServer extends EventEmitter {
    *
    * @param fn
    */
-  public use(fn: Middleware) {
+  public use(fn: any) {
     this.middlewares.push(fn);
   }