diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 49781ed..cc6da71 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -119,9 +119,6 @@ jobs:
           - "3.9"
           - "3.10"
           - "3.11"
-        include:
-          - os: ubuntu-20.04
-            python-version: "3.6"
     steps:
       - uses: actions/checkout@v3
       - id: setup-python
@@ -215,9 +212,6 @@ jobs:
           - "3.9"
           - "3.10"
           - "3.11"
-        include:
-          - os: ubuntu-20.04
-            python-version: "3.6"
     steps:
       - uses: actions/checkout@v3
       - id: setup-python
@@ -268,9 +262,6 @@ jobs:
           - "3.9"
           - "3.10"
           - "3.11"
-        include:
-          - os: ubuntu-20.04
-            python-version: "3.6"
     steps:
       - uses: actions/checkout@v3
       - id: setup-python
diff --git a/requirements.txt b/requirements.txt
index f073e44..8b75fe9 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,4 +1,3 @@
 # Note: Add any additional requirements to setup.py's install_requires field
 --editable .
-docker-compose
 wheel
diff --git a/setup.py b/setup.py
index 0dcea36..c208059 100644
--- a/setup.py
+++ b/setup.py
@@ -75,7 +75,6 @@ def get_version(version_file):
         # that you indicate whether you support Python 2, Python 3 or both.
         "Programming Language :: Python :: 3",
         "Programming Language :: Python :: 3 :: Only",
-        "Programming Language :: Python :: 3.6",
         "Programming Language :: Python :: 3.7",
         "Programming Language :: Python :: 3.8",
         "Programming Language :: Python :: 3.9",
@@ -83,7 +82,7 @@ def get_version(version_file):
         "Programming Language :: Python :: 3.11",
         "Programming Language :: Python :: Implementation :: CPython",
     ],
-    python_requires=">=3.6",
+    python_requires=">=3.7",
     # What does your project relate to?
     keywords="celery certificate-transparency cisa-directives",
     packages=find_packages(where="src"),
@@ -96,11 +95,9 @@ def get_version(version_file):
         "defusedxml",
         "dnspython",
         "docopt",
-        # MongoEngine 0.27.0 introduces a breaking change to the mongomock
-        # connection method. See #50 for more details.
-        "mongoengine >= 0.16.3,<0.27.0",
+        "mongoengine >= 0.27.0",
         "python-dateutil >= 2.7.5",
-        "PyYAML >=4.2b1",
+        "PyYAML >= 6.0.0",
         "redis >= 3.2.0",
         "requests <2.21,>=2.6.1",
         "schedule >= 0.4.2",
diff --git a/src/admiral/_version.py b/src/admiral/_version.py
index 4208ce3..39b2a5c 100644
--- a/src/admiral/_version.py
+++ b/src/admiral/_version.py
@@ -1,2 +1,2 @@
 """This file defines the version of this module."""
-__version__ = "1.3.3"
+__version__ = "1.4.0"
diff --git a/src/admiral/util/config.py b/src/admiral/util/config.py
index 65d412c..2ea3cc4 100644
--- a/src/admiral/util/config.py
+++ b/src/admiral/util/config.py
@@ -2,6 +2,7 @@
 
 # Third-Party Libraries
 from mongoengine import connect
+import pymongo
 import yaml
 
 
@@ -13,10 +14,10 @@ def load_config(filename="/run/secrets/config.yml"):
     return config
 
 
-def connect_from_config(config=None):
+def connect_from_config(config=None, client=pymongo.MongoClient):
     """Create connections from a confguration."""
     if not config:
         config = load_config()
     connections = config["connections"]
     for alias in connections.keys():
-        connect(host=connections[alias]["uri"], alias=alias)
+        connect(host=connections[alias]["uri"], mongo_client_class=client, alias=alias)
diff --git a/tests/cert_model_test.py b/tests/cert_model_test.py
index 2af9ebd..8037d41 100644
--- a/tests/cert_model_test.py
+++ b/tests/cert_model_test.py
@@ -7,6 +7,8 @@
 # Third-Party Libraries
 import dateutil.tz as tz
 import mongoengine
+from mongoengine import connect
+from mongomock import MongoClient
 import pytest
 
 # cisagov Libraries
@@ -48,11 +50,7 @@
 @pytest.fixture(scope="class", autouse=True)
 def connection():
     """Create connections for tests to use."""
-    # Third-Party Libraries
-    from mongoengine import connect
-
-    # TODO: Update this connection method. See #50 for more details.
-    connect(host="mongomock://localhost", alias="default")
+    connect(host="mongodb://localhost", mongo_client_class=MongoClient, alias="default")
 
 
 class TestCerts:
@@ -68,8 +66,8 @@ def test_empty_creation(self):
     def test_subjects(self):
         """Validate that subjects and trimmed_subjects are calulcated correctly."""
         cert = Cert()
-        cert.subjects = ["cisa.gov", "cyber.dhs.gov"]
-        assert set(cert.trimmed_subjects) == {"cisa.gov", "dhs.gov"}
+        cert.subjects = ["cisa.gov", "cyber.dhs.gov", "cisa.dhs.fed.us"]
+        assert set(cert.trimmed_subjects) == {"cisa.gov", "dhs.gov", "dhs.fed.us"}
 
     def test_simple_creation(self):
         """Create a new user, and save it."""
diff --git a/tests/data/valid_config.yml b/tests/data/valid_config.yml
index 45769dd..d747d8e 100644
--- a/tests/data/valid_config.yml
+++ b/tests/data/valid_config.yml
@@ -1,6 +1,6 @@
 ---
 connections:
   local:
-    uri: mongomock://local-user:example@mongo:27017/local
+    uri: mongodb://local-user:example@mongo:27017/local
   production:
-    uri: mongomock://production-user:example@mongo:27017/production
+    uri: mongodb://production-user:example@mongo:27017/production
diff --git a/tests/test_util.py b/tests/test_util.py
index 1365729..458cb1b 100644
--- a/tests/test_util.py
+++ b/tests/test_util.py
@@ -1,6 +1,7 @@
 """Test the functionality of the util sub-module."""
 
 # Third-Party Libraries
+import mongomock
 import pytest
 
 # cisagov Libraries
@@ -32,5 +33,4 @@ def test_load_config_valid():
 
 def test_connect_from_config_valid(valid_config):
     """Test that a valid configuration connects to appropriate connections."""
-    # TODO: Update this connection method. See #50 for more details.
-    util.connect_from_config(valid_config)
+    util.connect_from_config(valid_config, mongomock.MongoClient)