diff --git a/.dl_env.enc b/.dl_env.enc
deleted file mode 100644
index a970542..0000000
Binary files a/.dl_env.enc and /dev/null differ
diff --git a/.travis.yml b/.travis.yml
index 56de52c..ef8e9ea 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -6,20 +6,20 @@ cache: pip
 
 matrix:
   include:
-    - python: 3.5
+    - python: 3.6
       before_script:
         - >-
           [ -z "${TRAVIS_TAG}" ] && [ "${TRAVIS_PULL_REQUEST}" == "false" ]
           && openssl aes-256-cbc -K $encrypted_fc092b9428d6_key -iv $encrypted_fc092b9428d6_iv -in cis.env.enc -out cis.env -d
           && openssl aes-256-cbc -K $encrypted_d4a185972ecc_key -iv $encrypted_d4a185972ecc_iv -in pdns.env.enc -out pdns.env -d
           && openssl aes-256-cbc -K $encrypted_16de86179301_key -iv $encrypted_16de86179301_iv -in .transit_env.enc -out .transit_env -d
-          && openssl aes-256-cbc -K $encrypted_b4d7fa377f59_key -iv $encrypted_b4d7fa377f59_iv -in .dl_env.enc -out .dl_env -d
+          && openssl aes-256-cbc -K $encrypted_27cb64608ff6_key -iv $encrypted_27cb64608ff6_iv -in dl.env.enc -out dl.env -d
           || true
           [ -z "${TRAVIS_TAG}" ] && [ "${TRAVIS_PULL_REQUEST}" == "false" ]
           && openssl aes-256-cbc -K $encrypted_89a9eb4f9417_key -iv $encrypted_89a9eb4f9417_iv -in dns.env.enc -out dns.env -d || true
-    - python: 3.6
     - python: 3.7
     - python: 3.8
+    - python: 3.9
 
 before_install:
   - npm install npm@latest -g
@@ -45,7 +45,7 @@ deploy:
   script: npx semantic-release
   skip_cleanup: true
   on:
-    python: '3.5'
+    python: '3.6'
     branch: master
 
 - provider: pypi
@@ -54,5 +54,5 @@ deploy:
   repository: https://upload.pypi.org/legacy
   skip_cleanup: true
   on:
-    python: '3.5'
+    python: '3.6'
     tags: true
\ No newline at end of file
diff --git a/README.md b/README.md
index 7367ec1..31fa3dc 100644
--- a/README.md
+++ b/README.md
@@ -93,7 +93,7 @@ IBM Cloud services:
 
 - An [IBM Cloud][ibm-cloud-onboarding] account.
 - An IAM API key to allow the SDK to access your account. Create one [here](https://cloud.ibm.com/iam/apikeys).
-- Python 3.5.3 or above.
+- Python 3.6 or above.
 
 ## Installation
 
diff --git a/dl.env.enc b/dl.env.enc
new file mode 100644
index 0000000..3430182
Binary files /dev/null and b/dl.env.enc differ
diff --git a/ibm_cloud_networking_services/common.py b/ibm_cloud_networking_services/common.py
index 1df263d..51ee440 100644
--- a/ibm_cloud_networking_services/common.py
+++ b/ibm_cloud_networking_services/common.py
@@ -46,6 +46,7 @@ def get_user_agent():
 
 
 def get_sdk_headers(service_name, service_version, operation_id):
+    #pylint: disable=unused-argument
     """
     Get the request headers to be sent in requests by the SDK.
 
diff --git a/requirements-dev.txt b/requirements-dev.txt
index b4979ce..e380eaf 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -1,16 +1,10 @@
 # test dependencies
-pytest>=2.8.2
-responses>=0.10
-python_dotenv>=0.1.5
-pylint>=1.4.4
-tox>=2.9.1
+codecov>=2.1.0,<3.0.0
+coverage>=4.5.4
+pylint>=2.6.0,<3.0.0
+pytest>=6.2.1,<7.0.0
+pytest-cov>=2.2.1,<3.0.0
 pytest-rerunfailures>=3.1
-
-# code coverage
-coverage<5
-codecov>=1.6.3
-pytest-cov>=2.2.1
-
-# documentation
-recommonmark>=0.2.0
-Sphinx>=1.3.1
+responses>=0.12.1,<1.0.0
+tox>=3.2.0,<4.0.0
+python_dotenv>=0.1.5
diff --git a/requirements.txt b/requirements.txt
index 993c5aa..e5b472b 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,5 +1,3 @@
-jproperties
-requests>=2.0,<3.0
-python_dateutil>=2.5.3
-websocket-client==0.48.0
-ibm_cloud_sdk_core>=3.0.0
+requests>=2.24.0,<3.0
+python_dateutil>=2.5.3,<3.0.0
+ibm_cloud_sdk_core>=3.4.0,<4.0.0
diff --git a/setup.py b/setup.py
index 3953745..d54bfad 100644
--- a/setup.py
+++ b/setup.py
@@ -24,7 +24,9 @@
 PACKAGE_DESC = 'Python client library for IBM Cloud Networking Services'
 
 with open('requirements.txt') as f:
-    install_requires = [str(req) for req in pkg_resources.parse_requirements(f)]
+    install_requires = [
+        str(req) for req in pkg_resources.parse_requirements(f)
+    ]
 with open('requirements-dev.txt') as f:
     tests_require = [str(req) for req in pkg_resources.parse_requirements(f)]
 
@@ -38,35 +40,16 @@
     os.system('python setup.py sdist upload -r pypi')
     sys.exit()
 
-class PyTest(TestCommand):
-    def finalize_options(self):
-        TestCommand.finalize_options(self)
-        self.test_args = ['--strict', '--verbose', '--tb=long', 'test']
-        self.test_suite = True
-
-    def run_tests(self):
-        import pytest
-        errcode = pytest.main(self.test_args)
-        sys.exit(errcode)
-
-class PyTestUnit(PyTest):
-    def finalize_options(self):
-        self.test_args = ['--strict', '--verbose', '--tb=long', 'test/unit']
-
-class PyTestIntegration(PyTest):
-    def finalize_options(self):
-        self.test_args = ['--strict', '--verbose', '--tb=long', 'test/integration']
-
 with open("README.md", "r") as fh:
     readme = fh.read()
 
-setup(name=PACKAGE_NAME.replace('_', '-'),
+setup(
+      name=PACKAGE_NAME.replace('_', '-'),
       version=__version__,
       description=PACKAGE_DESC,
       license='Apache 2.0',
       install_requires=install_requires,
       tests_require=tests_require,
-      cmdclass={'test': PyTest, 'test_unit': PyTestUnit, 'test_integration': PyTestIntegration},
       author='IBM',
       author_email='devexdev@us.ibm.com',
       long_description=readme,
@@ -89,5 +72,4 @@ def finalize_options(self):
           'Topic :: Software Development :: Libraries :: Python Modules',
           'Topic :: Software Development :: Libraries :: Application Frameworks',
       ],
-      zip_safe=True
-     )
+      zip_safe=True)
\ No newline at end of file
diff --git a/test/integration/test_direct_link_provider_v2.py b/test/integration/test_direct_link_provider_v2.py
index ebf83d1..125b991 100644
--- a/test/integration/test_direct_link_provider_v2.py
+++ b/test/integration/test_direct_link_provider_v2.py
@@ -18,9 +18,9 @@
 
 # load the .env file containing your environment variables
 try:
-    load_dotenv(find_dotenv(filename=".dl_env"))
+    load_dotenv(find_dotenv(filename="dl.env"))
 except:
-    raise unittest.SkipTest('no .dl_env file loaded, skipping...')
+    raise unittest.SkipTest('no dl.env file loaded, skipping...')
 
 class TestDirectLinkProviderV2(unittest.TestCase):
     """ Test class for DirectLink Provider sdk functions """
diff --git a/test/integration/test_direct_link_v1.py b/test/integration/test_direct_link_v1.py
index 1835369..cef3f34 100644
--- a/test/integration/test_direct_link_v1.py
+++ b/test/integration/test_direct_link_v1.py
@@ -25,9 +25,9 @@
 
 # load the .env file containing your environment variables
 try:
-    load_dotenv(find_dotenv(filename=".dl_env"))
+    load_dotenv(find_dotenv(filename="dl.env"))
 except:
-    raise unittest.SkipTest('no .dl_env file loaded, skipping...')
+    raise unittest.SkipTest('no dl.env file loaded, skipping...')
 
 class TestDirectLinkV1(unittest.TestCase):
     """ Test class for DirectLink sdk functions """
diff --git a/test/integration/test_ssl_certificate_api_v1.py b/test/integration/test_ssl_certificate_api_v1.py
index ba70701..338204d 100644
--- a/test/integration/test_ssl_certificate_api_v1.py
+++ b/test/integration/test_ssl_certificate_api_v1.py
@@ -8,6 +8,7 @@
 import os
 import unittest
 import time
+import pytest
 from dotenv import load_dotenv, find_dotenv
 from ibm_cloud_networking_services import SslCertificateApiV1
 from ibm_cloud_sdk_core import ApiException
@@ -99,6 +100,7 @@ def test_1_list_custom_certificates(self):
         assert resp is not None
         assert resp.status_code == 200
 
+    @pytest.mark.skip(reason="No need to run this test case")
     def test_1_custom_certificate_actions(self):
         """ test method upload/delete/update/get given customized ssl certificate """
 
@@ -155,6 +157,7 @@ def test_1_custom_certificate_actions(self):
         assert resp is not None
         assert resp.status_code == 200
 
+    @pytest.mark.skip(reason="No need to run this test case")
     def test_1_universal_certificate_setting_actions(self):
         """ test method get/set custom ssl certificate settings """
 
diff --git a/tox.ini b/tox.ini
index 636c2a8..e04b5c7 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,7 +1,7 @@
 [tox]
-envlist = lint, py35, py36, py37, py38
+envlist = py37-lint, py36, py37, py38, py39
 
-[testenv:lint]
+[testenv:py37-lint]
 basepython = python3.7
 deps = pylint
 commands = pylint --rcfile=.pylintrc ibm_cloud_networking_services test