@@ -1,5 +1,6 @@
 import http = require("http");
 import type { Server as HTTPSServer } from "https";
+import type { Http2SecureServer } from "http2";
 import { createReadStream } from "fs";
 import { createDeflate, createGzip, createBrotliCompress } from "zlib";
 import accepts = require("accepts");
@@ -155,7 +156,7 @@ export class Server<
 * @private
 */
 _connectTimeout: number;
-private httpServer: http.Server | HTTPSServer;
+private httpServer: http.Server | HTTPSServer | Http2SecureServer;
 
 /**
 * Server constructor.
@@ -165,7 +166,7 @@ export class Server<
 */
 constructor(opts?: Partial<ServerOptions>);
 constructor(
-srv?: http.Server | HTTPSServer | number,
+srv?: http.Server | HTTPSServer | Http2SecureServer | number,
 opts?: Partial<ServerOptions>
 );
 constructor(
@@ -174,6 +175,7 @@ export class Server<
 | Partial<ServerOptions>
 | http.Server
 | HTTPSServer
+| Http2SecureServer
 | number,
 opts?: Partial<ServerOptions>
 );
@@ -183,6 +185,7 @@ export class Server<
 | Partial<ServerOptions>
 | http.Server
 | HTTPSServer
+| Http2SecureServer
 | number,
 opts: Partial<ServerOptions> = {}
 ) {
@@ -204,7 +207,9 @@ export class Server<
 this.sockets = this.of("/");
 this.opts = opts;
 if (srv || typeof srv == "number")
-this.attach(srv as http.Server | HTTPSServer | number);
+this.attach(
+srv as http.Server | HTTPSServer | Http2SecureServer | number
+);
 }
 
 /**
@@ -332,7 +337,7 @@ export class Server<
 * @return self
 */
 public listen(
-srv: http.Server | HTTPSServer | number,
+srv: http.Server | HTTPSServer | Http2SecureServer | number,
 opts: Partial<ServerOptions> = {}
 ): this {
 return this.attach(srv, opts);
@@ -346,7 +351,7 @@ export class Server<
 * @return self
 */
 public attach(
-srv: http.Server | HTTPSServer | number,
+srv: http.Server | HTTPSServer | Http2SecureServer | number,
 opts: Partial<ServerOptions> = {}
 ): this {
 if ("function" == typeof srv) {
@@ -452,7 +457,7 @@ export class Server<
 * @private
 */
 private initEngine(
-srv: http.Server | HTTPSServer,
+srv: http.Server | HTTPSServer | Http2SecureServer,
 opts: EngineOptions & AttachOptions
 ): void {
 // initialize engine
@@ -475,7 +480,9 @@ export class Server<
 * @param srv http server
 * @private
 */
-private attachServe(srv: http.Server | HTTPSServer): void {
+private attachServe(
+srv: http.Server | HTTPSServer | Http2SecureServer
+): void {
 debug("attaching client serving req handler");
 
 const evs = srv.listeners("request").slice(0);