diff --git a/.github/workflows/ci-stage-2.yml b/.github/workflows/ci-stage-2.yml
index 510cfd95..1f137615 100644
--- a/.github/workflows/ci-stage-2.yml
+++ b/.github/workflows/ci-stage-2.yml
@@ -13,20 +13,21 @@ jobs:
     strategy:
       matrix:
         os:
-          - ubuntu-20.04
           - ubuntu-22.04
           - ubuntu-24.04
-          - ubuntu-24.10
+          - ubuntu-26.04
+          - ubuntu-26.10
           - debian-testing
-          - fedora-39
-          - fedora-40
-          - rockylinux-8
+          - fedora-44
+          - fedora-45
+          - fedora-46
           - rockylinux-9
+          - rockylinux-10
 
     runs-on: ubuntu-latest
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
         with:
           submodules: recursive
 
diff --git a/docker/pythia-testenv b/docker/pythia-testenv
index c58bfb81..fd68bbef 100644
--- a/docker/pythia-testenv
+++ b/docker/pythia-testenv
@@ -2,7 +2,7 @@
 
 
 ARG BASE_IMAGE
-from ${BASE_IMAGE} as setup
+FROM ${BASE_IMAGE} AS setup
 ARG TEST_COVERAGE=no
 ARG PYTHON_COVERAGE=coverage3
 ENV TEST_COVERAGE=${TEST_COVERAGE} PYTHON_COVERAGE=${PYTHON_COVERAGE}
@@ -12,7 +12,7 @@ LABEL maintainer="Brad Aagaard <baagaard@usgs.gov>"
 USER ${TEST_USER}
 
 # ------------------------------------------------------------------------------
-from setup as configure
+FROM setup AS configure
 
 ENV src_dir=${TOPSRC_DIR}/pythia  build_dir=${TOPBUILD_DIR}/pythia
 COPY --chown=pylith-tester:pylith-tester . ${src_dir}
@@ -25,15 +25,15 @@ WORKDIR ${build_dir}
 RUN ${src_dir}/configure --enable-testing --prefix=${INSTALL_DIR} --enable-test-coverage=${TEST_COVERAGE} --with-python-coverage=${PYTHON_COVERAGE}  CPPFLAGS=-I${INSTALL_DIR}/include LDFLAGS="-L${INSTALL_DIR}/lib -L${INSTALL_DIR}/lib64 --coverage" CXXFLAGS="-g -O --coverage"
 
 # ------------------------------------------------------------------------------
-from configure as build
+FROM configure AS build
 
 RUN make -j$(nproc) && make install
 
-# Want source directory as current directory for running test coverage script via test runner.
+# Want source directory AS current directory for running test coverage script via test runner.
 WORKDIR ${src_dir}
 
 # ------------------------------------------------------------------------------
-from build as test
+FROM build AS test
 
 WORKDIR ${build_dir}
 RUN make check VERBOSE=1
diff --git a/tests/pytests/mpi/test_application.py b/tests/pytests/mpi/test_application.py
index c372b2aa..457a3618 100644
--- a/tests/pytests/mpi/test_application.py
+++ b/tests/pytests/mpi/test_application.py
@@ -25,8 +25,10 @@ def test_constructor(self):
         self.assertEqual("mpiapp", app.name)
 
     def test_run(self):
+        max_cores = 2
         app = MPIApp()
-        app.nodes = 3
+        n_cores = len(os.sched_getaffinity(0))
+        app.nodes = min(max_cores, n_cores) if n_cores > 0 else max_cores
         app.run(argv=["mpiapp", "--launcher.command=mpiexec -n ${nodes} -host localhost:${nodes}"])
         for node in range(app.nodes):
             filename = app.log_filename(node)