diff --git a/.github/workflows/ubuntu.yml b/.github/workflows/ubuntu.yml
index ef71fcf9c..bc42e31bb 100644
--- a/.github/workflows/ubuntu.yml
+++ b/.github/workflows/ubuntu.yml
@@ -94,7 +94,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        compiler: ['4', '5', '6', '7', '8', '9', '10', '11', '12', 'latest']
+        compiler: ['4.8', '4' '5', '6', '7', '8', '9', '10', '11', '12', 'latest']
     container: gcc:${{ matrix.compiler }}
     steps:
       - uses: actions/checkout@v3
@@ -120,19 +120,6 @@ jobs:
       - name: Build
         run: cmake --build build --target ci_test_compiler_default
 
-  ci_test_compilers:
-    runs-on: ubuntu-latest
-    container: ghcr.io/nlohmann/json-ci:v2.4.0
-    strategy:
-      matrix:
-        compiler: [g++-4.8, g++-4.9, g++-5, g++-6]
-    steps:
-      - uses: actions/checkout@v3
-      - name: Run CMake
-        run: cmake -S . -B build -DJSON_CI=On
-      - name: Build
-        run: cmake --build build --target ci_test_compiler_${{ matrix.compiler }}
-
   ci_test_standards:
     runs-on: ubuntu-latest
     container: ghcr.io/nlohmann/json-ci:v2.4.0
diff --git a/cmake/ci.cmake b/cmake/ci.cmake
index 13adbc823..26f8e88c8 100644
--- a/cmake/ci.cmake
+++ b/cmake/ci.cmake
@@ -905,30 +905,6 @@ add_custom_target(ci_cmake_flags
 # Use more installed compilers.
 ###############################################################################
 
-foreach(COMPILER g++-4.8 g++-4.9 g++-5 g++-6 g++-7 g++-8 g++-9 g++-10 g++-11 clang++-3.5 clang++-3.6 clang++-3.7 clang++-3.8 clang++-3.9 clang++-4.0 clang++-5.0 clang++-6.0 clang++-7 clang++-8 clang++-9 clang++-10 clang++-11 clang++-12 clang++-13 clang++-14)
-    find_program(COMPILER_TOOL NAMES ${COMPILER})
-    if (COMPILER_TOOL)
-        if ("${COMPILER}" STREQUAL "clang++-9")
-            # fix for https://github.com/nlohmann/json/pull/3101#issuecomment-998788786 / https://stackoverflow.com/a/64051725/266378
-            set(ADDITIONAL_FLAGS "-DCMAKE_CXX_FLAGS=--gcc-toolchain=/root/gcc/9")
-        else()
-            unset(ADDITIONAL_FLAGS)
-        endif()
-
-        add_custom_target(ci_test_compiler_${COMPILER}
-            COMMAND CXX=${COMPILER} ${CMAKE_COMMAND}
-                -DCMAKE_BUILD_TYPE=Debug -GNinja
-                -DJSON_BuildTests=ON -DJSON_FastTests=ON
-                -S${PROJECT_SOURCE_DIR} -B${PROJECT_BINARY_DIR}/build_compiler_${COMPILER}
-                ${ADDITIONAL_FLAGS}
-            COMMAND ${CMAKE_COMMAND} --build ${PROJECT_BINARY_DIR}/build_compiler_${COMPILER}
-            COMMAND cd ${PROJECT_BINARY_DIR}/build_compiler_${COMPILER} && ${CMAKE_CTEST_COMMAND} --parallel ${N} --exclude-regex "test-unicode" --output-on-failure
-            COMMENT "Compile and test with ${COMPILER}"
-        )
-    endif()
-    unset(COMPILER_TOOL CACHE)
-endforeach()
-
 add_custom_target(ci_test_compiler_default
     COMMAND ${CMAKE_COMMAND}
         -DCMAKE_BUILD_TYPE=Debug -GNinja