diff --git a/.github/workflows/CI.yml b/.github/workflows/CI.yml
index 532fb953..5915810d 100644
--- a/.github/workflows/CI.yml
+++ b/.github/workflows/CI.yml
@@ -63,18 +63,18 @@ jobs:
       # https://github.com/marketplace/actions/coveralls-python
       uses: AndreMiras/coveralls-python-action@develop
 
-  bionic_self_test:
-    # run_self_test in a ubuntu:18.04 image with only the minimal runtime dependencies installed
+  focal_self_test:
+    # run_self_test in a ubuntu:20.04 image with only the minimal runtime dependencies installed
     runs-on: ubuntu-20.04
     steps:
     - uses: actions/checkout@v2
     - name: docker build
       run: |
-        mkdir bionic_self_test
-        cp requirements.txt bionic_self_test
+        mkdir focal_self_test
+        cp requirements.txt focal_self_test
 
-        cat << 'EOF' > bionic_self_test/Dockerfile
-          FROM ubuntu:18.04
+        cat << 'EOF' > focal_self_test/Dockerfile
+          FROM ubuntu:20.04
           ENV LC_ALL C.UTF-8
           ENV LANG C.UTF-8
           RUN apt-get -qq update && DEBIAN_FRONTEND=noninteractive apt-get -qq install -y python3-pip
@@ -93,11 +93,11 @@ jobs:
           # expectation -- mount miniwdl source tree at /home/wdler/miniwdl
           CMD env -C miniwdl python3 -m WDL run_self_test
         EOF
-        docker build -t miniwdl_bionic_self_test bionic_self_test
+        docker build -t miniwdl_focal_self_test focal_self_test
     - name: miniwdl run_self_test
       run: |
         docker run \
           --group-add $(stat -c %g /var/run/docker.sock) -v /var/run/docker.sock:/var/run/docker.sock \
           -v $(pwd):/home/wdler/miniwdl -v /tmp:/tmp \
           -e AWS_EC2_METADATA_DISABLED=true \
-          miniwdl_bionic_self_test
+          miniwdl_focal_self_test
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index d5db0474..2b47b67a 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -22,8 +22,8 @@ The Makefile has a few typical flows:
 
 - `make` or `make test` runs the full test suite with code coverage report (takes several minutes)
 - `make qtest` runs most of the tests more quickly (by omitting some slower cases, and not tracking coverage)
-- `make pretty` reformats the code with [black](https://github.com/python/black)
-- `make check` validates the code with [Pylint](https://www.pylint.org/) and [Pyre](https://pyre-check.org/)
+- `make pretty` reformats the code with `ruff format`
+- `make check` validates the code with `ruff check` and `mypy`
 
 To quickly run only a relevant subset of the tests, you can e.g. `python3 -m unittest -f tests/test_5stdlib.py` or `python3 -m unittest -f tests.test_5stdlib.TestStdLib.test_glob`.
 
diff --git a/README.md b/README.md
index 079db6c0..80bd403f 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 # miniwdl
-**[Workflow Description Language](http://openwdl.org/) local runner & developer toolkit for Python 3.6+**
+**[Workflow Description Language](http://openwdl.org/) local runner & developer toolkit for Python 3.8+**
 
 ![Project Status](https://img.shields.io/badge/status-stable-green.svg)
 [![MIT license](https://img.shields.io/badge/license-MIT-brightgreen.svg)](https://github.com/chanzuckerberg/miniwdl/blob/main/LICENSE)
@@ -9,7 +9,7 @@
 
 ## Install miniwdl
 
-Installation requires Python 3.6+, pip3 (or conda) and Docker (or Podman/Singularity/udocker). Linux preferred; [macOS (Intel) compatible with extra steps](https://github.com/chanzuckerberg/miniwdl/issues/145). More detail in [full documentation](https://miniwdl.readthedocs.io/en/latest/getting_started.html).
+Installation requires Python 3.8+, pip3 (or conda) and Docker (or Podman/Singularity/udocker). Linux preferred; [macOS (Intel) compatible with extra steps](https://github.com/chanzuckerberg/miniwdl/issues/145). More detail in [full documentation](https://miniwdl.readthedocs.io/en/latest/getting_started.html).
 
 - Install with pip [![PyPI version](https://img.shields.io/pypi/v/miniwdl.svg)](https://pypi.org/project/miniwdl/) : run `pip3 install miniwdl`
 - Install with conda [![Anaconda-Server Badge](https://anaconda.org/conda-forge/miniwdl/badges/version.svg)](https://anaconda.org/conda-forge/miniwdl) : run `conda install -c conda-forge miniwdl`
diff --git a/setup.py b/setup.py
index e0fc369f..7e1a2974 100755
--- a/setup.py
+++ b/setup.py
@@ -4,5 +4,5 @@
 setuptools.setup(
     setup_requires=['pbr'],
     pbr=True,
-    python_requires=">3.6.0",
+    python_requires=">3.8.0",
 )