diff --git a/.github/workflows/docbuild.yml b/.github/workflows/docbuild.yml
index e57d9a0..81b6d51 100644
--- a/.github/workflows/docbuild.yml
+++ b/.github/workflows/docbuild.yml
@@ -8,7 +8,7 @@ jobs:
     strategy:
       max-parallel: 4
       matrix:
-        python-version: [3.6, 3.7, 3.8, 3.9]
+        python-version: ["3.10", "3.11"]
 
     steps:
       - name: Checkout repo
diff --git a/.github/workflows/pythonpackage.yml b/.github/workflows/pythonpackage.yml
index 47a5834..9dd97c8 100644
--- a/.github/workflows/pythonpackage.yml
+++ b/.github/workflows/pythonpackage.yml
@@ -8,7 +8,7 @@ jobs:
     strategy:
       max-parallel: 8
       matrix:
-        python-version: [3.6, 3.7, 3.8, 3.9]
+        python-version: ["3.10", "3.11"]
 
     steps:
       - name: Checkout repo
@@ -19,9 +19,9 @@ jobs:
           python-version: ${{ matrix.python-version }}
       - name: Install software
         run: |
-          python -m pip install --upgrade pip --use-feature=2020-resolver
-          python -m pip install coveralls --use-feature=2020-resolver
-          python -m pip install .[dev] --use-feature=2020-resolver
+          python -m pip install --upgrade pip
+          python -m pip install coveralls
+          python -m pip install .[dev]
           python -m pip install https://github.com/bboe/coveralls-python/archive/github_actions.zip
       - name: Configure
         run: |
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index a30267f..c25c21a 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -1,6 +1,5 @@
 repos:
 -   repo: https://github.com/python/black
-    rev: 22.1.0
+    rev: 23.7.0
     hooks:
     - id: black
-      language_version: python3.9
diff --git a/cloudknot/aws/base_classes.py b/cloudknot/aws/base_classes.py
index 620fb91..6896fd6 100644
--- a/cloudknot/aws/base_classes.py
+++ b/cloudknot/aws/base_classes.py
@@ -251,6 +251,7 @@ def get_s3_params():
 
         # Use set_s3_params to check for name availability
         # and write to config file
+        bucket = bucket.replace("_", "-")  # S3 does not allow underscores
         set_s3_params(bucket=bucket, policy=policy, sse=sse)
 
         if policy is None:
diff --git a/cloudknot/cloudknot.py b/cloudknot/cloudknot.py
index 9251735..38da5fa 100644
--- a/cloudknot/cloudknot.py
+++ b/cloudknot/cloudknot.py
@@ -5,10 +5,9 @@
 import logging
 import os
 
-try:
-    from collections.abc import Iterable, namedtuple
-except ImportError:
-    from collections import Iterable, namedtuple
+from collections.abc import Iterable
+from collections import namedtuple
+
 from concurrent.futures import ThreadPoolExecutor
 
 from . import aws
diff --git a/cloudknot/data/docker_reqs_ref_data/py3/ref1/Dockerfile b/cloudknot/data/docker_reqs_ref_data/py3/ref1/Dockerfile
index 5b07533..6f0dc50 100644
--- a/cloudknot/data/docker_reqs_ref_data/py3/ref1/Dockerfile
+++ b/cloudknot/data/docker_reqs_ref_data/py3/ref1/Dockerfile
@@ -13,18 +13,17 @@ RUN pip install --no-cache-dir -r /tmp/requirements.txt
 # Create a default user. Available via runtime flag `--user cloudknot-user`.
 # Add user to "staff" group.
 # Give user a home directory.
-RUN (id -u cloudknot-user >/dev/null 2>&1 || useradd cloudknot-user) \
-    && addgroup cloudknot-user staff \
-    && mkdir -p /home/cloudknot-user \
-    && chown -R cloudknot-user:staff /home/cloudknot-user
+RUN groupadd -f staff \
+    && useradd --create-home --groups staff "cloudknot-user"
 
-ENV HOME /home/cloudknot-user
+# Copy the python script
+COPY --chown="cloudknot-user" "unit-testing-func.py" "/home/cloudknot-user/"
+
+# Set user
+USER "cloudknot-user"
 
 # Set working directory
-WORKDIR /home/cloudknot-user
+WORKDIR "/home/cloudknot-user"
 
 # Set entrypoint
-ENTRYPOINT ["python", "/home/cloudknot-user/unit-testing-func.py"]
-
-# Copy the python script
-COPY unit-testing-func.py /home/cloudknot-user/
+ENTRYPOINT ["/home/cloudknot-user/unit-testing-func.py"]
diff --git a/cloudknot/data/docker_reqs_ref_data/py3/ref1/unit-testing-func.py b/cloudknot/data/docker_reqs_ref_data/py3/ref1/unit-testing-func.py
index 55ddaa2..ecaeb66 100644
--- a/cloudknot/data/docker_reqs_ref_data/py3/ref1/unit-testing-func.py
+++ b/cloudknot/data/docker_reqs_ref_data/py3/ref1/unit-testing-func.py
@@ -1,3 +1,4 @@
+#!/usr/bin/env python3
 import boto3
 import cloudpickle
 import os
diff --git a/cloudknot/data/docker_reqs_ref_data/py3/ref2/Dockerfile b/cloudknot/data/docker_reqs_ref_data/py3/ref2/Dockerfile
index f332d1c..d4cbfe4 100644
--- a/cloudknot/data/docker_reqs_ref_data/py3/ref2/Dockerfile
+++ b/cloudknot/data/docker_reqs_ref_data/py3/ref2/Dockerfile
@@ -13,18 +13,17 @@ RUN pip install --no-cache-dir -r /tmp/requirements.txt
 # Create a default user. Available via runtime flag `--user unit-test-username`.
 # Add user to "staff" group.
 # Give user a home directory.
-RUN (id -u unit-test-username >/dev/null 2>&1 || useradd unit-test-username) \
-    && addgroup unit-test-username staff \
-    && mkdir -p /home/unit-test-username \
-    && chown -R unit-test-username:staff /home/unit-test-username
+RUN groupadd -f staff \
+    && useradd --create-home --groups staff "unit-test-username"
 
-ENV HOME /home/unit-test-username
+# Copy the python script
+COPY --chown="unit-test-username" "test-func-input.py" "/home/unit-test-username/"
+
+# Set user
+USER "unit-test-username"
 
 # Set working directory
-WORKDIR /home/unit-test-username
+WORKDIR "/home/unit-test-username"
 
 # Set entrypoint
-ENTRYPOINT ["python", "/home/unit-test-username/test-func-input.py"]
-
-# Copy the python script
-COPY test-func-input.py /home/unit-test-username/
+ENTRYPOINT ["/home/unit-test-username/test-func-input.py"]
diff --git a/cloudknot/data/docker_reqs_ref_data/py3/ref2/test-func-input.py b/cloudknot/data/docker_reqs_ref_data/py3/ref2/test-func-input.py
index 55ddaa2..ecaeb66 100644
--- a/cloudknot/data/docker_reqs_ref_data/py3/ref2/test-func-input.py
+++ b/cloudknot/data/docker_reqs_ref_data/py3/ref2/test-func-input.py
@@ -1,3 +1,4 @@
+#!/usr/bin/env python3
 import boto3
 import cloudpickle
 import os
diff --git a/cloudknot/templates/Dockerfile.template b/cloudknot/templates/Dockerfile.template
index cf1b8d8..259aa92 100644
--- a/cloudknot/templates/Dockerfile.template
+++ b/cloudknot/templates/Dockerfile.template
@@ -13,18 +13,17 @@ RUN pip install --no-cache-dir -r /tmp/requirements.txt${github_installs_string}
 # Create a default user. Available via runtime flag `--user ${username}`.
 # Add user to "staff" group.
 # Give user a home directory.
-RUN (id -u ${username} >/dev/null 2>&1 || useradd ${username}) \
-    && addgroup ${username} staff \
-    && mkdir -p /home/${username} \
-    && chown -R ${username}:staff /home/${username}
+RUN groupadd -f staff \
+    && useradd --create-home --groups staff "${username}"
 
-ENV HOME /home/${username}
+# Copy the python script
+COPY --chown="${username}" "${script_base_name}" "/home/${username}/"
+
+# Set user
+USER "${username}"
 
 # Set working directory
-WORKDIR /home/${username}
+WORKDIR "/home/${username}"
 
 # Set entrypoint
-ENTRYPOINT ["python", "/home/${username}/${script_base_name}"]
-
-# Copy the python script
-COPY ${script_base_name} /home/${username}/
+ENTRYPOINT ["/home/${username}/${script_base_name}"]
diff --git a/cloudknot/templates/script.template b/cloudknot/templates/script.template
index 6383ff1..d885e2e 100644
--- a/cloudknot/templates/script.template
+++ b/cloudknot/templates/script.template
@@ -1,3 +1,4 @@
+#!/usr/bin/env python3
 import boto3
 import cloudpickle
 import os
diff --git a/pyproject.toml b/pyproject.toml
index 6d944aa..9d2a6ab 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -27,7 +27,7 @@ exclude = '''
     | build
     | dist
   )/
-  | foo.py           # also separately exclude a file named foo.py in
-                     # the root of the project
+  | _version.py
+  | cli.py
 )
 '''
diff --git a/setup.cfg b/setup.cfg
index 86c839b..cc361d2 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -33,9 +33,9 @@ setup_requires =
   setuptools_scm
 python_requires = >=3.6
 install_requires =
-    awscli
-    boto3>=1.5.21
-    botocore>=1.8.36
+    boto3>=1.34.31
+    awscli>=1.32.31
+    botocore>=1.34.31
     cloudpickle
     docker>=3.0.0
     pipreqs>=0.4.11
@@ -53,18 +53,17 @@ console_scripts =
 
 [options.extras_require]
 dev =
-    black==20.8b1
+    black==23.7.0
     coverage==5.3
     flake8==3.8.3
     numpydoc==1.1.0
-    moto>=2.2.13.dev2
-    responses==0.12.0
-    pre-commit==2.9.2
+    moto[cloudformation]==4.1.5
+    pre-commit==3.3.3
     pydocstyle==5.1.1
     pytest-cov==2.10.1
     pytest-xdist[psutil]==2.1.0
-    pytest==6.0.1
-    sphinx==3.2.1
+    pytest==7.4.0
+    sphinx==5.0.0
 maint =
     rapidfuzz==0.12.2