diff --git a/.github/workflows/pythonpackage.yml b/.github/workflows/pythonpackage.yml
index ebf86e7..b0395e1 100644
--- a/.github/workflows/pythonpackage.yml
+++ b/.github/workflows/pythonpackage.yml
@@ -8,11 +8,9 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: [3.6, 3.7, 3.8, 3.9, pypy3]
+        python-version: [3.6, 3.7, 3.8, 3.9, pypy3, '3.10.0-rc.1']
         os: [
           ubuntu-20.04,
-          ubuntu-18.04,
-          ubuntu-16.04,
           macOS-latest,
           windows-latest,
         ]
@@ -34,9 +32,7 @@ jobs:
         pip install flake8
         pip install xmltodict==0.12.0
         # stop the build if there are Python syntax errors or undefined names
-        flake8 json2xml/
-        # exit-zero treats all errors as warnings. The GitHub editor is 127 chars wide
-        flake8 . --count --exit-zero --max-complexity=10 --max-line-length=127 --statistics
+        flake8 json2xml/ --exit-zero
     - name: Test with pytest
       run: |
         python setup.py test
diff --git a/json2xml/json2xml.py b/json2xml/json2xml.py
index 3817d94..3809e83 100644
--- a/json2xml/json2xml.py
+++ b/json2xml/json2xml.py
@@ -1,4 +1,5 @@
 # -*- coding: utf-8 -*-
+from typing import Optional, Any
 from xml.dom.minidom import parseString
 from json2xml import dicttoxml
 
@@ -17,7 +18,7 @@ def __init__(
         self.attr_type = attr_type
         self.root = root
 
-    def to_xml(self):
+    def to_xml(self) -> Optional[Any]:
         """
         Convert to xml using dicttoxml.dicttoxml and then pretty print it.
         """
diff --git a/json2xml/utils.py b/json2xml/utils.py
index f8fe893..ecb2ac9 100644
--- a/json2xml/utils.py
+++ b/json2xml/utils.py
@@ -1,5 +1,6 @@
 """Utils methods to convert XML data to dict from various sources"""
 import json
+from typing import Dict, Optional
 import requests
 
 
@@ -15,7 +16,8 @@ class StringReadError(Exception):
     pass
 
 
-def readfromjson(filename: str) -> dict:
+
+def readfromjson(filename: str) -> Dict[str, str]:
     """
     Reads a json string and emits json string
     """
@@ -32,7 +34,7 @@ def readfromjson(filename: str) -> dict:
         raise JSONReadError("Invalid JSON File")
 
 
-def readfromurl(url: str, params: dict = None) -> dict:
+def readfromurl(url: str, params: Optional[Dict[str, str]] = None) -> Dict[str, str]:
     """
     Loads json from an URL over the internets
     """
@@ -45,7 +47,7 @@ def readfromurl(url: str, params: dict = None) -> dict:
     raise URLReadError("URL is not returning correct response")
 
 
-def readfromstring(jsondata: str) -> dict:
+def readfromstring(jsondata: str) -> Dict[str, str]:
     """
     Loads json from string
     """
diff --git a/setup.cfg b/setup.cfg
index c6a46a6..8ffa5d3 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -29,3 +29,4 @@ disallow_untyped_defs = true
 no_implicit_optional = true
 warn_redundant_casts = true
 warn_unused_ignores = true
+ignore_missing_imports = true
diff --git a/setup.py b/setup.py
index f40a868..a1a3d94 100644
--- a/setup.py
+++ b/setup.py
@@ -22,13 +22,15 @@
     author="Vinit Kumar",
     author_email="mail@vinitkumar.me",
     classifiers=[
-        "Development Status :: 2 - Pre-Alpha",
+        "Development Status :: 6 - Mature",
         "Intended Audience :: Developers",
         "License :: OSI Approved :: Apache Software License",
         "Natural Language :: English",
-        "Programming Language :: Python :: 3.5",
         "Programming Language :: Python :: 3.6",
         "Programming Language :: Python :: 3.7",
+        "Programming Language :: Python :: 3.8",
+        "Programming Language :: Python :: 3.9",
+        "Programming Language :: Python :: 3.10",
     ],
     description="Simple Python Library to convert JSON to XML",
     install_requires=requirements,