diff --git a/.circleci/Dockerfile.slackware b/.circleci/Dockerfile.slackware
deleted file mode 100644
index 4b6d96f95..000000000
--- a/.circleci/Dockerfile.slackware
+++ /dev/null
@@ -1,50 +0,0 @@
-ARG TAG
-FROM vbatts/slackware:${TAG}
-ARG PYTHON_VERSION
-
-ENV WHEELHOUSE_PATH /tmp/wheelhouse
-ENV VIRTUALENV_PATH /tmp/venv
-# This will get updated by the CircleCI checkout step.
-ENV BUILD_SRC_ROOT /tmp/project
-
-# Be careful with slackpkg.  If the package name given doesn't match anything,
-# slackpkg still claims to succeed but you're totally screwed.  Slackware
-# updates versions of packaged software so including too much version prefix
-# is a good way to have your install commands suddenly begin not installing
-# anything.
-RUN slackpkg update && \
-    slackpkg install \
-        openssh-7 git-2 \
-        ca-certificates \
-        sudo-1 \
-        make-4 \
-        automake-1 \
-        kernel-headers \
-        glibc-2 \
-        binutils-2 \
-        gcc-5 \
-        gcc-g++-5 \
-        python-${PYTHON_VERSION} \
-        libffi-3 \
-        libyaml-0 \
-        sqlite-3 \
-        icu4c-56 \
-        libmpc-1 </dev/null && \
-    slackpkg upgrade \
-        openssl-1 </dev/null
-
-# neither virtualenv nor pip is packaged.
-# do it the hard way.
-# and it is extra hard since it is slackware.
-RUN slackpkg install \
-        cyrus-sasl-2 \
-        curl-7 </dev/null && \
-    curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py && \
-    python get-pip.py && \
-    pip install virtualenv
-
-# Get the project source.  This is better than it seems.  CircleCI will
-# *update* this checkout on each job run, saving us more time per-job.
-COPY . ${BUILD_SRC_ROOT}
-
-RUN "${BUILD_SRC_ROOT}"/.circleci/prepare-image.sh "${WHEELHOUSE_PATH}" "${VIRTUALENV_PATH}" "${BUILD_SRC_ROOT}" "python${PYTHON_VERSION}"
diff --git a/.circleci/config.yml b/.circleci/config.yml
index f5b33b106..e75a6ba0f 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -11,10 +11,13 @@ workflows:
           requires:
             - "debian-9"
 
-      - "ubuntu-18.04"
+      - "ubuntu-20.04"
+      - "ubuntu-18.04":
+          requires:
+            - "ubuntu-20.04"
       - "ubuntu-16.04":
           requires:
-            - "ubuntu-18.04"
+            - "ubuntu-20.04"
 
       - "fedora-29"
       - "fedora-28":
@@ -23,8 +26,6 @@ workflows:
 
       - "centos-8"
 
-      - "slackware-14.2"
-
       - "nixos-19.09"
 
       # Test against PyPy 2.7
@@ -68,10 +69,10 @@ workflows:
       - "build-image-debian-9"
       - "build-image-ubuntu-16.04"
       - "build-image-ubuntu-18.04"
+      - "build-image-ubuntu-20.04"
       - "build-image-fedora-28"
       - "build-image-fedora-29"
       - "build-image-centos-8"
-      - "build-image-slackware-14.2"
       - "build-image-pypy-2.7-buster"
       - "build-image-python36-ubuntu"
 
@@ -283,6 +284,13 @@ jobs:
       TAHOE_LAFS_TOX_ENVIRONMENT: "py36"
 
 
+  ubuntu-20.04:
+    <<: *DEBIAN
+    docker:
+      - image: "tahoelafsci/ubuntu:20.04"
+        user: "nobody"
+
+
   centos-8: &RHEL_DERIV
     docker:
       - image: "tahoelafsci/centos:8-py2"
@@ -318,26 +326,6 @@ jobs:
         user: "nobody"
 
 
-  slackware-14.2:
-    docker:
-      - image: "tahoelafsci/slackware:14.2-py2"
-        user: "nobody"
-
-    environment: *UTF_8_ENVIRONMENT
-
-    # pip cannot install packages if the working directory is not readable.
-    # We want to run a lot of steps as nobody instead of as root.
-    working_directory: "/tmp/project"
-
-    steps:
-      - "checkout"
-      - run: *SETUP_VIRTUALENV
-      - run: *RUN_TESTS
-      - store_test_results: *STORE_TEST_RESULTS
-      - store_artifacts: *STORE_TEST_LOG
-      - store_artifacts: *STORE_OTHER_ARTIFACTS
-      - run: *SUBMIT_COVERAGE
-
   nixos-19.09:
     docker:
       # Run in a highly Nix-capable environment.
@@ -510,6 +498,14 @@ jobs:
       PYTHON_VERSION: "3"
 
 
+  build-image-ubuntu-20.04:
+    <<: *BUILD_IMAGE
+
+    environment:
+      DISTRO: "ubuntu"
+      TAG: "20.04"
+
+
   build-image-centos-8:
     <<: *BUILD_IMAGE
 
@@ -537,15 +533,6 @@ jobs:
       TAG: "29"
 
 
-  build-image-slackware-14.2:
-    <<: *BUILD_IMAGE
-
-    environment:
-      DISTRO: "slackware"
-      TAG: "14.2"
-      PYTHON_VERSION: "2"
-
-
   build-image-pypy-2.7-buster:
     <<: *BUILD_IMAGE
 
diff --git a/newsfragments/3323.removed b/newsfragments/3323.removed
new file mode 100644
index 000000000..356b4b2af
--- /dev/null
+++ b/newsfragments/3323.removed
@@ -0,0 +1 @@
+Slackware 14.2 is no longer a Tahoe-LAFS supported platform.
diff --git a/newsfragments/3328.installation b/newsfragments/3328.installation
new file mode 100644
index 000000000..7b08ffdc4
--- /dev/null
+++ b/newsfragments/3328.installation
@@ -0,0 +1 @@
+Tahoe-LAFS now supports Ubuntu 20.04.
\ No newline at end of file