diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 930fc710..e9c909e3 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -24,10 +24,8 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ['3.6', '3.7', '3.8', '3.9', '3.10', 'pypy-3.9']
+        python-version: ['3.7', '3.8', '3.9', '3.10', '3.11', 'pypy-3.9']
         include:
-          - python-version: '3.6'
-            pytest-args: --ignore=tests/__generated__/test_recursive_postponned.py
           - python-version: '3.10'
             pytest-args: --cov=apischema --cov-branch --cov-report=xml --cov-report=html
     steps:
diff --git a/apischema/json_schema/types.py b/apischema/json_schema/types.py
index 659bbb86..daf4b9ee 100644
--- a/apischema/json_schema/types.py
+++ b/apischema/json_schema/types.py
@@ -34,6 +34,9 @@ class JsonType(str, Enum):
     def from_type(cls: Type) -> "JsonType":
         return TYPE_TO_JSON_TYPE[cls]
 
+    def __str__(self) -> str:
+        return self.value
+
 
 class JsonTypes(Dict[type, JsonType]):
     def __missing__(self, key):
diff --git a/apischema/typing.py b/apischema/typing.py
index a89e7e8b..132163c4 100644
--- a/apischema/typing.py
+++ b/apischema/typing.py
@@ -94,7 +94,9 @@ def get_args(tp):
     except ImportError:
         pass
 
-if sys.version_info >= (3, 7):
+if sys.version_info >= (3, 11):
+    from typing import _collect_parameters as _collect_type_vars
+elif sys.version_info >= (3, 7):
     from typing import _collect_type_vars  # type: ignore
 else:
     from typing import _type_vars as _collect_type_vars
@@ -274,7 +276,7 @@ def typing_origin(origin: Any) -> Any:
 
 def is_type(tp: Any) -> bool:
     """isinstance is not enough because in py39: isinstance(list[int], type) == True"""
-    return isinstance(tp, type) and not get_args(tp)
+    return isinstance(tp, type) and not get_args(tp) and tp is not Any
 
 
 def is_union(tp: Any) -> bool:
diff --git a/examples/flattened.py b/examples/flattened.py
index 2e673d39..f033df14 100644
--- a/examples/flattened.py
+++ b/examples/flattened.py
@@ -20,7 +20,7 @@ class RootJsonSchema:
     schema: str | UndefinedType = field(default=Undefined, metadata=alias("$schema"))
     defs: list[JsonSchema] = field(default_factory=list, metadata=alias("$defs"))
     # This field schema is flattened inside the owning one
-    json_schema: JsonSchema = field(default=JsonSchema(), metadata=flatten)
+    json_schema: JsonSchema = field(default_factory=JsonSchema, metadata=flatten)
 
 
 data = {
diff --git a/examples/ordering.py b/examples/ordering.py
index 6d61d085..2d666197 100644
--- a/examples/ordering.py
+++ b/examples/ordering.py
@@ -31,12 +31,12 @@ def age(self) -> int:
 
 
 user = User("Harry", "Potter", "London", date(1980, 7, 31))
-dump = """{
+dump = f"""{{
     "trigram": "hpr",
     "firstname": "Harry",
     "lastname": "Potter",
-    "age": 41,
+    "age": {user.age},
     "birthdate": "1980-07-31",
     "address": "London"
-}"""
+}}"""
 assert json.dumps(serialize(User, user), indent=4) == dump
diff --git a/setup.cfg b/setup.cfg
index d737efe3..5e3ecf3e 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -5,6 +5,9 @@ ignore = E203, E302, E501, W503, E731, E741
 [isort]
 profile = black
 
+[tool:pytest]
+asyncio_mode = auto
+
 [coverage:report]
 ;fail_under = 100
 precision = 2
@@ -17,4 +20,4 @@ exclude_lines =
     if TYPE_CHECKING
     stop_signature_abuse()
     if sys.version_info
-    def __getattr__(name):
\ No newline at end of file
+    def __getattr__(name):
diff --git a/tests/requirements.txt b/tests/requirements.txt
index cf850048..2f3e6e22 100644
--- a/tests/requirements.txt
+++ b/tests/requirements.txt
@@ -6,7 +6,7 @@ docstring-parser==0.13
 pydantic==1.9.0
 pytest==7.0.1
 pytest-cov==3.0.0
-pytest-asyncio==0.16.0
+pytest-asyncio==0.17.2
 SQLAlchemy==1.4.32
 typing-extensions==4.0.1
 Cython==0.29.27