diff --git a/.github/workflows/build-publish.yml b/.github/workflows/build-publish.yml
index 6dd286c..af90f07 100644
--- a/.github/workflows/build-publish.yml
+++ b/.github/workflows/build-publish.yml
@@ -22,8 +22,6 @@ jobs:
     strategy:
       matrix:
         r_version:
-          - 4.2.3
-          - 4.3.3
           - 4.4.2
 
     steps:
diff --git a/Dockerfile b/Dockerfile
index 3398c58..808ebd4 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -5,10 +5,10 @@ ARG R_VERSION
 ARG CRAN_VERSION
 
 # Set default locale
-ENV LANG C.UTF-8
+ENV LANG=C.UTF-8
 
 # Set default timezone
-ENV TZ UTC
+ENV TZ=UTC
 
 # copy over helpers script
 COPY helpers.R /etc/R/helpers.R
@@ -38,7 +38,6 @@ RUN apt-get update -q \
       locales \
       lsb-release \
       pandoc \
-      pandoc-citeproc \
       perl \
       software-properties-common \
       sudo \
@@ -60,18 +59,6 @@ RUN distro=$(lsb_release -c | awk '{print $2}') \
  && echo "deb-src [signed-by=/etc/apt/keyrings/cloud.r-project.org.gpg] https://cloud.r-project.org/bin/linux/ubuntu ${distro}-$CRAN_VERSION/" >> /etc/apt/sources.list.d/cloud.r-project.org.list \
  && rm -rf $GNUPGHOME
 
-# add CRAN modules package configurations
-# https://launchpad.net/~c2d4u.team/+archive/ubuntu/c2d4u4.0+
-RUN distro=$(lsb_release -c | awk '{print $2}') \
- && keyid=6E12762B81063D17BDDD3142F142A4D99F16EB04 \
- && export GNUPGHOME="$(mktemp -d)" \
- && gpg --recv-keys --keyserver keyserver.ubuntu.com $keyid \
- && mkdir -p /etc/apt/keyrings \
- && gpg --export $keyid > /etc/apt/keyrings/c2d4u.team.gpg \
- && echo "deb [signed-by=/etc/apt/keyrings/c2d4u.team.gpg] https://ppa.launchpadcontent.net/c2d4u.team/c2d4u4.0+/ubuntu/ ${distro} main" > /etc/apt/sources.list.d/c2d4u.team.list \
- && echo "deb-src [signed-by=/etc/apt/keyrings/c2d4u.team.gpg] https://ppa.launchpadcontent.net/c2d4u.team/c2d4u4.0+/ubuntu/ ${distro} main" >> /etc/apt/sources.list.d/c2d4u.team.list \
- && rm -rf $GNUPGHOME
-
 # install TinyTeX
 RUN curl -sSL "https://yihui.org/tinytex/install-bin-unix.sh" | sh \
  && /root/.TinyTeX/bin/*/tlmgr path remove \
diff --git a/Makevars b/Makevars
index 3cc4228..7bf9ed1 100644
--- a/Makevars
+++ b/Makevars
@@ -1,5 +1,5 @@
-UBUNTU_VERSION:=22.04
-R_VERSION:=4.2.2
+UBUNTU_VERSION:=24.04
+R_VERSION:=4.4.2
 CRAN_VERSION:=cran40
 
 MAINTAINER:=Chris Stefano <virtualstaticvoid@gmail.com>
diff --git a/README.md b/README.md
index 50f1ac2..e9eab21 100644
--- a/README.md
+++ b/README.md
@@ -374,8 +374,8 @@ available on [GitHub Container Registry][ghcr], including:
 
 | Ubuntu Version | R Version | Base Tag      | Build Tag     | Shiny Tag     | Plumber Tag     |
 |----------------|-----------|---------------|---------------|---------------|-----------------|
-| `22.04`        | `4.4.2`   | `latest`      | `build`       | `shiny`       | `plumber`       |
-| `22.04`        | `4.4.2`   |               | `4.4.2-build` | `4.4.2-shiny` | `4.4.2-plumber` |
+| `24.04`        | `4.4.2`   | `latest`      | `build`       | `shiny`       | `plumber`       |
+| `24.04`        | `4.4.2`   |               | `4.4.2-build` | `4.4.2-shiny` | `4.4.2-plumber` |
 | `22.04`        | `4.3.3`   |               | `4.3.3-build` | `4.3.3-shiny` | `4.3.3-plumber` |
 | `22.04`        | `4.2.3`   |               | `4.2.3-build` | `4.2.3-shiny` | `4.2.3-plumber` |
 | `22.04`        | `4.2.2`   |               | `4.2.2-build` | `4.2.2-shiny` | `4.2.2-plumber` |
diff --git a/test/units/README.md b/test/units/README.md
index d75f07f..05f7585 100644
--- a/test/units/README.md
+++ b/test/units/README.md
@@ -1,3 +1,3 @@
-Tests taken and adapted from https://github.com/rstudio/r-docker/tree/master/test suite.
+Tests taken and adapted from https://github.com/rstudio/r-docker/tree/main/test suite.
 
-See https://github.com/rstudio/r-docker/blob/master/LICENSE for LICENSE.
+See https://github.com/rstudio/r-docker/blob/main/LICENSE for LICENSE.
diff --git a/test/units/test.R b/test/units/test.R
index c4e1b01..9f8a6ca 100644
--- a/test/units/test.R
+++ b/test/units/test.R
@@ -46,8 +46,10 @@ tryCatch(capabilities(), warning = function(w) {
 
 # Check graphics devices
 # https://stat.ethz.ch/R-manual/R-devel/library/grDevices/html/Devices.html
-for (dev_name in c("png", "jpeg", "tiff", "svg", "bmp", "pdf", "postscript",
-                   "cairo_pdf", "cairo_ps")) {
+devices <- c("png", "jpeg", "tiff", "svg", "bmp", "pdf", "postscript",
+             if (getRversion() < "4.4.0") c("xfig", "pictex"),
+             "cairo_pdf", "cairo_ps")
+for (dev_name in devices) {
   # Skip unsupported graphics devices (e.g. tiff in R >= 3.3 on CentOS 6)
   if (dev_name %in% names(capabilities()) && capabilities(dev_name) == FALSE) {
     next
diff --git a/test/units/test.sh b/test/units/test.sh
index d448c6d..888c740 100755
--- a/test/units/test.sh
+++ b/test/units/test.sh
@@ -20,6 +20,7 @@ Rscript $DIR/testpkg/tests/test.R
 
 # Check that TinyTeX and Pandoc were installed correctly
 tlmgr --version
+pandoc --version
 echo -e '# Title\ncontent' | pandoc --output $DIR/test.pdf
 rm $DIR/test.pdf