Fix ALPN handling
diff --git a/examples/client.cc b/examples/client.cc
index 684ebff..e9e3385 100644
--- a/examples/client.cc
+++ b/examples/client.cc
@@ -899,8 +899,8 @@
 
   switch (version_) {
   case NGTCP2_PROTO_VER_D19:
-    alpn = reinterpret_cast<const uint8_t *>(NGTCP2_ALPN_D19);
-    alpnlen = str_size(NGTCP2_ALPN_D19);
+    alpn = reinterpret_cast<const uint8_t *>(NGTCP2_ALPN_H3);
+    alpnlen = str_size(NGTCP2_ALPN_H3);
     break;
   }
   if (alpn) {
diff --git a/examples/server.cc b/examples/server.cc
index 6467605..355cfed 100644
--- a/examples/server.cc
+++ b/examples/server.cc
@@ -3411,8 +3411,8 @@
 
   switch (version) {
   case NGTCP2_PROTO_VER_D19:
-    alpn = reinterpret_cast<const uint8_t *>(NGTCP2_ALPN_D19);
-    alpnlen = str_size(NGTCP2_ALPN_D19);
+    alpn = reinterpret_cast<const uint8_t *>(NGTCP2_ALPN_H3);
+    alpnlen = str_size(NGTCP2_ALPN_H3);
     break;
   default:
     if (!config.quiet) {
@@ -3429,16 +3429,13 @@
       return SSL_TLSEXT_ERR_OK;
     }
   }
-  // Just select alpn for now.
-  *out = reinterpret_cast<const uint8_t *>(alpn + 1);
-  *outlen = alpn[0];
 
   if (!config.quiet) {
-    std::cerr << "Client did not present ALPN " << NGTCP2_ALPN_D19 + 1
+    std::cerr << "Client did not present ALPN " << NGTCP2_ALPN_H3 + 1
               << std::endl;
   }
 
-  return SSL_TLSEXT_ERR_OK;
+  return SSL_TLSEXT_ERR_NOACK;
 }
 } // namespace
 
diff --git a/lib/includes/ngtcp2/ngtcp2.h b/lib/includes/ngtcp2/ngtcp2.h
index 9b64c7f..dc2c525 100644
--- a/lib/includes/ngtcp2/ngtcp2.h
+++ b/lib/includes/ngtcp2/ngtcp2.h
@@ -161,10 +161,10 @@
    supports. */
 #define NGTCP2_PROTO_VER_MAX NGTCP2_PROTO_VER_D19
 
-/* NGTCP2_ALPN_* is a serialized form of ALPN protocol identifier this
-   library supports.  Notice that the first byte is the length of the
-   following protocol identifier. */
-#define NGTCP2_ALPN_D19 "\x5h3-19"
+/* NGTCP2_ALPN_H3 is a serialized form of HTTP/3 ALPN protocol
+   identifier this library supports.  Notice that the first byte is
+   the length of the following protocol identifier. */
+#define NGTCP2_ALPN_H3 "\x5h3-19"
 
 #define NGTCP2_MAX_PKTLEN_IPV4 1252
 #define NGTCP2_MAX_PKTLEN_IPV6 1232