diff --git a/.circleci/config.yml b/.circleci/config.yml
index adb8304db..86c32a65e 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -8,32 +8,35 @@ jobs:
         type: string
       topology:
         type: string
-    machine:
-      image: ubuntu-2404:edge
+    #machine:
+    #  image: ubuntu-2504:edge
+    docker:
+      - image: ubuntu:25.04
     resource_class: arm.medium
     environment:
-      CC: gcc-14
-      CXX: g++-14
+      CC: gcc-15
+      CXX: g++-15
     steps:
       - run: |
+          apt-get update --quiet=2 || apt-get update --quiet=2 || apt-get update --quiet=2
+          apt-get install -y sudo
+          sudo apt-get install -y git # Updating and installing sudo and git is only neccesary in a container.
+          # Installing sudo is just so that the later commands using sudo can be the same whether in a container or not.
           export REPO_HTTPS=`echo "$CIRCLE_REPOSITORY_URL" | sed "s|git@github.com:|https://github.com/|g"`
           git clone -b "$CIRCLE_BRANCH" "$REPO_HTTPS" . --depth=1
       - run: |
-          sudo apt-add-repository -y universe
-          sudo apt-get install -y gcc-14 g++-14
+          sudo apt-get install -y gcc-15 g++-15
           sudo apt-get install -y cmake
           sudo apt-get install -y hwloc libhwloc-dev
       - run: |
           mkdir build
-          pushd build
+          cd build
           cmake -DCMAKE_BUILD_TYPE=Release -DQTHREADS_SCHEDULER=<< parameters.scheduler >> -DQTHREADS_TOPOLOGY=<< parameters.topology >> ..
           make -j2 VERBOSE=1
-          popd
       - run:
           command: |
-              pushd build
+              cd build
               CTEST_OUTPUT_ON_FAILURE=1 timeout --foreground -k 10s 2m make test VERBOSE=1
-              popd
           no_output_timeout: 180s
 
   arm_clang:
@@ -42,35 +45,40 @@ jobs:
         type: string
       topology:
         type: string
-    machine:
-      image: ubuntu-2404:edge
+    #machine:
+    #  image: ubuntu-2504:edge
+    docker:
+      - image: ubuntu:25.04
     resource_class: arm.medium
     environment:
       CC: clang-20
       CXX: clang++-20
     steps:
       - run: |
+          apt-get update --quiet=2 || apt-get update --quiet=2 || apt-get update --quiet=2
+          apt-get install -y sudo
+          sudo apt-get install -y git # Updating and installing sudo and git is only neccesary in a container.
+          # Installing sudo is just so that the later commands using sudo can be the same whether in a container or not.
           export REPO_HTTPS=`echo "$CIRCLE_REPOSITORY_URL" | sed "s|git@github.com:|https://github.com/|g"`
           git clone -b "$CIRCLE_BRANCH" "$REPO_HTTPS" . --depth=1
       - run: |
-          sudo apt-add-repository -y universe
-          sudo apt-get install -y gcc-14 g++-14
+          sudo apt-get install -y gnupg wget # Only needed in container.
+          sudo apt-get install -y gcc-15 g++-15
           sudo apt-get install -y cmake
           sudo apt-get install -y hwloc libhwloc-dev
-          wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | sudo apt-key add -
-          sudo apt-add-repository -y 'deb https://apt.llvm.org/noble/ llvm-toolchain-noble-20 main'
+          # tzdata is required by clang and has to be installed carefully to avoid user prompts stalling the script.
+          ln -fs /usr/share/zoneinfo/America/New_York /etc/localtime
+          DEBIAN_FRONTEND=noninteractive sudo apt-get install -y --no-install-recommends tzdata
           sudo apt-get install -y clang-20
       - run: |
           mkdir build
-          pushd build
+          cd build
           cmake -DCMAKE_BUILD_TYPE=Release -DQTHREADS_SCHEDULER=<< parameters.scheduler >> -DQTHREADS_TOPOLOGY=<< parameters.topology >> ..
           make -j2 VERBOSE=1
-          popd
       - run:
           command: |
-              pushd build
+              cd build
               CTEST_OUTPUT_ON_FAILURE=1 timeout --foreground -k 10s 2m make test VERBOSE=1
-              popd
           no_output_timeout: 180s
 
   arm_sanitizers:
@@ -81,8 +89,10 @@ jobs:
         type: string
       sanitizer:
         type: string
-    machine:
-      image: ubuntu-2404:edge
+    #machine:
+    #  image: ubuntu-2504:edge
+    docker:
+      - image: ubuntu:25.04
     resource_class: arm.medium
     environment:
       CC: clang-20
@@ -94,25 +104,29 @@ jobs:
       ASAN_OPTIONS: "check_initialization_order=1"
     steps:
       - run: |
+          apt-get update --quiet=2 || apt-get update --quiet=2 || apt-get update --quiet=2
+          apt-get install -y sudo
+          sudo apt-get install -y git # Updating and installing sudo and git is only neccesary in a container.
+          # Installing sudo is just so that the later commands using sudo can be the same whether in a container or not.
           export REPO_HTTPS=`echo "$CIRCLE_REPOSITORY_URL" | sed "s|git@github.com:|https://github.com/|g"`
           git clone -b "$CIRCLE_BRANCH" "$REPO_HTTPS" . --depth=1
       - run: |
-          sudo apt-add-repository -y universe
-          sudo apt-get install -y gcc-14 g++-14
+          sudo apt-get install -y gnupg wget # Only needed in container.
+          sudo apt-get install -y gcc-15 g++-15
           sudo apt-get install -y cmake
           sudo apt-get install -y hwloc libhwloc-dev
-          wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | sudo apt-key add -
-          sudo apt-add-repository -y 'deb https://apt.llvm.org/noble/ llvm-toolchain-noble-20 main'
+          # tzdata is required by clang and has to be installed carefully to avoid user prompts stalling the script.
+          ln -fs /usr/share/zoneinfo/America/New_York /etc/localtime
+          DEBIAN_FRONTEND=noninteractive sudo apt-get install -y --no-install-recommends tzdata
           sudo apt-get install -y clang-20
       - run: |
           mkdir build
-          pushd build
+          cd build
           cmake -DCMAKE_BUILD_TYPE=Release -DQTHREADS_SCHEDULER=<< parameters.scheduler >> -DQTHREADS_TOPOLOGY=<< parameters.topology >> ..
           make -j2 VERBOSE=1
-          popd
       - run:
           command: |
-              pushd build
+              cd build
               if [[ "<< parameters.sanitizer >>" == "thread" ]]; then cd test/basics; fi
               CTEST_OUTPUT_ON_FAILURE=1 timeout --foreground -k 10s 4m make test VERBOSE=1
           no_output_timeout: 180s
@@ -190,13 +204,13 @@ jobs:
           if [ ${MACHINE_TYPE} == 'x86_64' ]; then echo 'deb [signed-by=/usr/share/keyrings/nvidia-hpcsdk-archive-keyring.gpg] https://developer.download.nvidia.com/hpc-sdk/ubuntu/amd64 /' | sudo tee /etc/apt/sources.list.d/nvhpc.list; fi
           if [ ${MACHINE_TYPE} == 'aarch64' ]; then echo 'deb [signed-by=/usr/share/keyrings/nvidia-hpcsdk-archive-keyring.gpg] https://developer.download.nvidia.com/hpc-sdk/ubuntu/arm64 /' | sudo tee /etc/apt/sources.list.d/nvhpc.list; fi
           sudo apt-get update -y
-          sudo apt-get install -y nvhpc-24-9
+          sudo apt-get install -y nvhpc-25-3
           sudo apt-get install -y cmake
           sudo apt-get install -y hwloc libhwloc-dev
       - run: |
           export MACHINE_TYPE=`uname -m`
-          if [ ${MACHINE_TYPE} == 'x86_64' ]; then export PATH="$PATH:/opt/nvidia/hpc_sdk/Linux_x86_64/24.9/compilers/bin"; fi
-          if [ ${MACHINE_TYPE} == 'aarch64' ]; then export PATH="$PATH:/opt/nvidia/hpc_sdk/Linux_aarch64/24.9/compilers/bin"; fi
+          if [ ${MACHINE_TYPE} == 'x86_64' ]; then export PATH="$PATH:/opt/nvidia/hpc_sdk/Linux_x86_64/25.3/compilers/bin"; fi
+          if [ ${MACHINE_TYPE} == 'aarch64' ]; then export PATH="$PATH:/opt/nvidia/hpc_sdk/Linux_aarch64/25.3/compilers/bin"; fi
           nvc --version
           mkdir build
           pushd build
diff --git a/.cirrus.yml b/.cirrus.yml
index 1345b4e7e..3a7becffc 100644
--- a/.cirrus.yml
+++ b/.cirrus.yml
@@ -74,7 +74,7 @@ freebsd_task:
 
 arm_linux_task:
   arm_container:
-    image: gcc:14-bookworm
+    image: gcc:15-bookworm
   timeout_in: 5m
   matrix:
     env:
@@ -109,7 +109,7 @@ arm_linux_task:
 
 arm_linux_clang_task:
   arm_container:
-    image: gcc:14-bookworm
+    image: gcc:15-bookworm
   timeout_in: 5m
   matrix:
     env:
diff --git a/.github/workflows/CI.yml b/.github/workflows/CI.yml
index 6e713bad3..5d6acbfd9 100644
--- a/.github/workflows/CI.yml
+++ b/.github/workflows/CI.yml
@@ -14,7 +14,7 @@ jobs:
     continue-on-error: true
     strategy:
       matrix:
-        gcc_version: [9, 10, 11, 12, 13]
+        gcc_version: [9, 10, 11, 12, 13, 14]
         scheduler: [nemesis, sherwood, distrib]
         topology: [hwloc, binders, no]
     env:
@@ -113,7 +113,7 @@ jobs:
       run: |
         wget -O - https://apt.repos.intel.com/intel-gpg-keys/GPG-PUB-KEY-INTEL-SW-PRODUCTS.PUB | sudo apt-key add - && break || sleep 1
         sudo apt-add-repository 'deb https://apt.repos.intel.com/oneapi all main' && break || sleep 1
-        sudo apt-get install intel-oneapi-compiler-dpcpp-cpp-2024.2
+        sudo apt-get install intel-oneapi-compiler-dpcpp-cpp-2025.1
         source /opt/intel/oneapi/setvars.sh
         icx -v
     - name: build qthreads
@@ -197,7 +197,7 @@ jobs:
         sudo apt-get install gcc-13 g++-13
     - name: install aocc
       run: |
-        wget -nv -O aocc.deb https://download.amd.com/developer/eula/aocc/aocc-4-2/aocc-compiler-4.2.0_1_amd64.deb
+        wget -nv -O aocc.deb https://download.amd.com/developer/eula/aocc/aocc-5-0/aocc-compiler-5.0.0_1_amd64.deb
         sudo apt install -y ./aocc.deb
         clang -v
     - name: build qthreads
@@ -259,6 +259,7 @@ jobs:
 
   sanitizers:
     runs-on: ubuntu-24.04
+    container: ubuntu:25.04
     continue-on-error: true
     strategy:
       matrix:
@@ -291,35 +292,39 @@ jobs:
     - uses: actions/checkout@v4
     - if:  ${{ ! matrix.use_libcxx }}
       run: |
-        sudo apt-get install gcc-14 g++-14
+        apt-get update
+        apt-get install -y sudo # Updating and installing sudo is only neccesary in a container.
+        # Installing sudo is just so that the later commands using sudo can be the same whether in a container or not.
+        sudo apt-get install -y gcc-15 g++-15
+        sudo apt-get install -y cmake # Only needed in a container. Cmake is installed by default on VM images.
     - name: install compiler
       run: |
+        sudo apt-get install -y software-properties-common # Only needed in container.
         wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | sudo apt-key add - && break || sleep 1
-        sudo apt-add-repository 'deb https://apt.llvm.org/noble/ llvm-toolchain-noble-20 main' && break || sleep 1
-        sudo apt-get install clang-20
+        sudo apt-add-repository 'deb https://apt.llvm.org/oracular/ llvm-toolchain-oracular-20 main' && break || sleep 1
+        sudo apt-get install -y clang-20
     - if: ${{ matrix.use_libcxx }}
-      run: sudo apt-get install libc++-20-dev libc++abi-20-dev
+      run: sudo apt-get install -y libc++-20-dev libc++abi-20-dev
     - if: ${{ matrix.topology != 'no' }}
       run: |
-        sudo apt-get install hwloc libhwloc-dev
+        sudo apt-get install -y hwloc libhwloc-dev
         hwloc-ls --version
     - name: build qthreads
       run: |
         mkdir build
-        pushd build
+        cd build
         cmake -DCMAKE_BUILD_TYPE=Release -DQTHREADS_SCHEDULER=${{ matrix.scheduler }} -DQTHREADS_TOPOLOGY=${{ matrix.topology }} ..
         make -j2 VERBOSE=1
-        popd
     - name: run tests
       run: |
-        pushd build
-        if [[ "${{ matrix.sanitizer }}" == "thread" ]]; then cd test/basics; fi
+        cd build
+        if [ "${{ matrix.sanitizer }}" = "thread" ]; then cd test/basics; fi
         CTEST_OUTPUT_ON_FAILURE=1 timeout -k 10s --foreground 18m make test VERBOSE=1
-        popd
       timeout-minutes: 19
 
   linux-thorough:
     runs-on: ubuntu-24.04
+    container: ubuntu:25.04
     continue-on-error: true
     strategy:
       matrix:
@@ -332,37 +337,40 @@ jobs:
           - compiler: gcc
             use_libcxx: true
     env:
-      CC: ${{ matrix.compiler == 'gcc' && 'gcc-14' || 'clang-20' }}
-      CXX: ${{ matrix.compiler == 'gcc' && 'g++-14' || 'clang++-20' }}
+      CC: ${{ matrix.compiler == 'gcc' && 'gcc-15' || 'clang-20' }}
+      CXX: ${{ matrix.compiler == 'gcc' && 'g++-15' || 'clang++-20' }}
       CXXFLAGS: ${{ matrix.use_libcxx && '-stdlib=libc++' || '' }}
       QTHREADS_ENABLE_ASSERTS: ${{ matrix.use_asserts && '--enable-asserts' || '' }}
     steps:
     - uses: actions/checkout@v4
     - run: |
-        sudo apt-get install gcc-14 g++-14
+        apt-get update
+        apt-get install -y sudo # Updating and installing sudo is only neccesary in a container.
+        # Installing sudo is just so that the later commands using sudo can be the same whether in a container or not.
+        sudo apt-get install -y gcc-15 g++-15
+        sudo apt-get install -y cmake # Only needed in a container. Cmake is installed by default on VM images.
     - if: ${{ matrix.compiler == 'clang' }}
       run: |
+        sudo apt-get install -y software-properties-common # Only needed in container.
         wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | sudo apt-key add - && break || sleep 1
-        sudo apt-add-repository 'deb https://apt.llvm.org/noble/ llvm-toolchain-noble-20 main' && break || sleep 1
-        sudo apt-get install clang-20
+        sudo apt-add-repository 'deb https://apt.llvm.org/oracular/ llvm-toolchain-oracular-20 main' && break || sleep 1
+        sudo apt-get install -y clang-20
     - if: ${{ matrix.use_libcxx }}
-      run: sudo apt-get install libc++-20-dev libc++abi-20-dev
+      run: sudo apt-get install -y libc++-20-dev libc++abi-20-dev
     - if: ${{ matrix.topology != 'no' }}
       run: |
-        sudo apt-get install hwloc libhwloc-dev
+        sudo apt-get install -y hwloc libhwloc-dev
         hwloc-ls --version
     - name: build qthreads
       run: |
         mkdir build
-        pushd build
+        cd build
         cmake -DCMAKE_BUILD_TYPE=${{ matrix.build_type }} -DQTHREADS_SCHEDULER=${{ matrix.scheduler }} -DQTHREADS_TOPOLOGY=${{ matrix.topology }} ..
         make -j2 VERBOSE=1
-        popd
     - name: run tests
       run: |
-        pushd build
+        cd build
         CTEST_OUTPUT_ON_FAILURE=1 timeout -k 10s --foreground 18m make test VERBOSE=1
-        popd
       timeout-minutes: 19
 
   clang-format:
diff --git a/src/ds/qlfqueue.c b/src/ds/qlfqueue.c
index c76b2642b..a10f6e5f3 100644
--- a/src/ds/qlfqueue.c
+++ b/src/ds/qlfqueue.c
@@ -100,7 +100,8 @@ API_FUNC int qlfqueue_enqueue(qlfqueue_t *q, void *elem) {
 
     next = tail->next;
     if (next != NULL) { /* tail not pointing to last node */
-      (void)qthread_cas_ptr((void **)&(q->tail), (void *)tail, next);
+      atomic_store_explicit(
+        (void *_Atomic *)&q->tail, next, memory_order_relaxed);
       continue;
     }
     /* tail must be pointing to the last node */
@@ -108,7 +109,7 @@ API_FUNC int qlfqueue_enqueue(qlfqueue_t *q, void *elem) {
       break; /* success! */
     }
   }
-  (void)qthread_cas_ptr((void **)&(q->tail), (void *)tail, node);
+  atomic_store_explicit((void *_Atomic *)&q->tail, node, memory_order_relaxed);
   hazardous_ptr(0,
                 NULL); // release the ptr (avoid hazardptr resource exhaustion)
   return QTHREAD_SUCCESS;
@@ -139,7 +140,8 @@ API_FUNC void *qlfqueue_dequeue(qlfqueue_t *q) {
     if (next_ptr == NULL) { return NULL; } /* queue is empty */
     if (head == tail) {                    /* tail is falling behind! */
       /* advance tail ptr... */
-      (void)qthread_cas_ptr((void **)&(q->tail), (void *)tail, next_ptr);
+      atomic_store_explicit(
+        (void *_Atomic *)&q->tail, next_ptr, memory_order_relaxed);
       continue;
     }
     /* read value before CAS, otherwise another dequeue might free the next node
diff --git a/src/qthread.c b/src/qthread.c
index 5f8e90999..778d3ec56 100644
--- a/src/qthread.c
+++ b/src/qthread.c
@@ -999,7 +999,8 @@ void API_FUNC qthread_finalize(void) {
       qt_threadqueue_enqueue(qlib->shepherds[i].ready, t);
       if (!atomic_load_explicit(&qlib->shepherds[i].workers[j].active,
                                 memory_order_relaxed)) {
-        (void)QT_CAS(qlib->shepherds[i].workers[j].active, 0, 1);
+        atomic_store_explicit(
+          &qlib->shepherds[i].workers[j].active, 1, memory_order_relaxed);
       }
     }
   }
diff --git a/src/shepherds.c b/src/shepherds.c
index ac21fbfbf..7170aafec 100644
--- a/src/shepherds.c
+++ b/src/shepherds.c
@@ -155,7 +155,7 @@ int API_FUNC qthread_disable_shepherd(qthread_shepherd_id_t const shep) {
   }
   qthread_internal_incr(
     &(qlib->nshepherds_active), &(qlib->nshepherds_active_lock), (aligned_t)-1);
-  (void)QT_CAS(qlib->shepherds[shep].active, 1, 0);
+  atomic_store_explicit(&qlib->shepherds[shep].active, 0, memory_order_relaxed);
   return QTHREAD_SUCCESS;
 }
 
@@ -164,7 +164,7 @@ void API_FUNC qthread_enable_shepherd(qthread_shepherd_id_t const shep) {
   assert(shep < qlib->nshepherds);
   qthread_internal_incr(
     &(qlib->nshepherds_active), &(qlib->nshepherds_active_lock), 1);
-  (void)QT_CAS(qlib->shepherds[shep].active, 0, 1);
+  atomic_store_explicit(&qlib->shepherds[shep].active, 1, memory_order_relaxed);
 }
 
 /***************************************************************************
diff --git a/src/workers.c b/src/workers.c
index 1c96f715f..46f06c310 100644
--- a/src/workers.c
+++ b/src/workers.c
@@ -32,7 +32,8 @@ int API_FUNC qthread_disable_worker(qthread_worker_id_t const w) {
     return QTHREAD_NOT_ALLOWED;
   }
 
-  (void)QT_CAS(qlib->shepherds[shep].workers[worker].active, 1, 0);
+  atomic_store_explicit(
+    &qlib->shepherds[shep].workers[worker].active, 0, memory_order_relaxed);
   qlib->nworkers_active--; // decrement active count
 
   if (worker == 0) { qthread_disable_shepherd(shep); }
@@ -52,7 +53,8 @@ void API_FUNC qthread_enable_worker(qthread_worker_id_t const w) {
   if (worker < qlib->nworkerspershep) {
     qthread_internal_incr(
       &(qlib->nworkers_active), &(qlib->nworkers_active_lock), 1);
-    (void)QT_CAS(qlib->shepherds[shep].workers[worker].active, 0, 1);
+    atomic_store_explicit(
+      &qlib->shepherds[shep].workers[worker].active, 1, memory_order_relaxed);
   }
 }