diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 8a527a1..2839db5 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -22,7 +22,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
-        python: ['3.8', '3.9', '3.10', '3.11', '3.12']
+        python: ['3.9', '3.10', '3.11', '3.12', '3.13', '3.14', 'pypy-3.11']
       fail-fast: false
     runs-on: ${{ matrix.os }}
     steps:
diff --git a/.gitignore b/.gitignore
index b6e4761..ce75252 100644
--- a/.gitignore
+++ b/.gitignore
@@ -127,3 +127,6 @@ dmypy.json
 
 # Pyre type checker
 .pyre/
+
+mise.toml
+requirements*.txt
diff --git a/examples/app.py b/examples/app.py
index 5726ced..ebfaf57 100644
--- a/examples/app.py
+++ b/examples/app.py
@@ -23,12 +23,12 @@ class UserSchema(ma.Schema):
     class Meta:
         description = 'This schema represents a user'
 
-    id = ma.String(dump_only=True, description="The user's id")
-    username = ma.String(required=True, description="The user's username")
-    first_name = ma.String(description="The user's first name")
-    last_name = ma.String(description="The user's last name")
-    age = ma.Integer(description="The user's age")
-    password = ma.String(load_only=True, description="The user's password")
+    id = ma.String(dump_only=True, metadata={"description": "The user's id"})
+    username = ma.String(required=True, metadata={"description": "The user's username"})
+    first_name = ma.String(metadata={"description": "The user's first name"})
+    last_name = ma.String(metadata={"description": "The user's last name"})
+    age = ma.Integer(metadata={"description": "The user's age"})
+    password = ma.String(load_only=True, metadata={"description": "The user's password"})
 
 
 @app.get('/users')
diff --git a/examples/app_with_class_views.py b/examples/app_with_class_views.py
index 87c9350..4faf867 100644
--- a/examples/app_with_class_views.py
+++ b/examples/app_with_class_views.py
@@ -25,12 +25,12 @@ class UserSchema(ma.Schema):
     class Meta:
         description = 'This schema represents a user'
 
-    id = ma.String(dump_only=True, description="The user's id")
-    username = ma.String(required=True, description="The user's username")
-    first_name = ma.String(description="The user's first name")
-    last_name = ma.String(description="The user's last name")
-    age = ma.Integer(description="The user's age")
-    password = ma.String(load_only=True, description="The user's password")
+    id = ma.String(dump_only=True, metadata={"description": "The user's id"})
+    username = ma.String(required=True, metadata={"description": "The user's username"})
+    first_name = ma.String(metadata={"description": "The user's first name"})
+    last_name = ma.String(metadata={"description": "The user's last name"})
+    age = ma.Integer(metadata={"description": "The user's age"})
+    password = ma.String(load_only=True, metadata={"description": "The user's password"})
 
 
 class GetUsersEndpoint(MethodView):
diff --git a/pyproject.toml b/pyproject.toml
index a2d5a79..1aa1937 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -11,7 +11,7 @@ classifiers = [
     "License :: OSI Approved :: MIT License",
     "Operating System :: OS Independent",
 ]
-requires-python = ">=3.6"
+requires-python = ">=3.9"
 dependencies = [
     "flask >= 1.1.0",
     "flask-marshmallow",
@@ -32,6 +32,9 @@ Homepage = "https://github.com/miguelgrinberg/apifairy"
 docs = [
     "sphinx",
 ]
+dev = [
+    "tox",
+]
 
 [tool.setuptools]
 zip-safe = false
diff --git a/tests/test_apifairy.py b/tests/test_apifairy.py
index ec1d8f1..238dbbb 100644
--- a/tests/test_apifairy.py
+++ b/tests/test_apifairy.py
@@ -23,7 +23,7 @@ class Schema(ma.Schema):
     class Meta:
         unknown = EXCLUDE
 
-    id = ma.Integer(default=123)
+    id = ma.Integer(dump_default=123)
     name = ma.Str(required=True)
 
 
@@ -31,17 +31,17 @@ class Schema2(ma.Schema):
     class Meta:
         unknown = EXCLUDE
 
-    id2 = ma.Integer(default=123)
+    id2 = ma.Integer(dump_default=123)
     name2 = ma.Str(required=True)
 
 
 class FooSchema(ma.Schema):
-    id = ma.Integer(default=123)
+    id = ma.Integer(dump_default=123)
     name = ma.Str()
 
 
 class QuerySchema(ma.Schema):
-    id = ma.Integer(missing=1)
+    id = ma.Integer(load_default=1)
 
 
 class FormSchema(ma.Schema):
diff --git a/tox.ini b/tox.ini
index 2c2834d..cceb75d 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,14 +1,15 @@
 [tox]
-envlist=flake8,py38,py39,py310,py311,py312,pypy3,docs
+envlist=flake8,py39,py310,py311,py312,py313,py314,pypy3,docs
 skip_missing_interpreters=True
 
 [gh-actions]
 python =
-    3.8: py38
     3.9: py39
     3.10: py310
     3.11: py311
     3.12: py312
+    3.13: py313
+    3.14: py314
     pypy-3: pypy3
 
 [testenv]