diff --git a/sanic/http/constants.py b/sanic/http/constants.py
index 35890712..6b914c1a 100644
--- a/sanic/http/constants.py
+++ b/sanic/http/constants.py
@@ -21,5 +21,6 @@ class Stage(Enum):
 
 
 class HTTP(Enum):
+    AUTO = 0
     VERSION_1 = 1
     VERSION_3 = 3
diff --git a/setup.py b/setup.py
index ea6f285a..5dc874c3 100644
--- a/setup.py
+++ b/setup.py
@@ -148,6 +148,7 @@ extras_require = {
     "docs": docs_require,
     "all": all_require,
     "ext": ["sanic-ext"],
+    "http3": ["aioquic"],
 }
 
 setup_kwargs["install_requires"] = requirements