diff --git a/.github/workflows/core_build.yml b/.github/workflows/core_build.yml
index 431ed6e67..a5e41b01e 100644
--- a/.github/workflows/core_build.yml
+++ b/.github/workflows/core_build.yml
@@ -24,7 +24,7 @@ jobs:
             compiler: clang # default in 18.04 is clang 6
             modules: without
           - os: ubuntu-18.04
-            compiler: gcc # default in 18.04 is gcc 7
+            compiler: gcc8
             modules: without
           - os: ubuntu-20.04
             compiler: gcc # default in 20.04 is gcc 9
diff --git a/apps/ci/ci-conf.sh b/apps/ci/ci-conf.sh
index 42f9674b8..b3a75448a 100644
--- a/apps/ci/ci-conf.sh
+++ b/apps/ci/ci-conf.sh
@@ -28,6 +28,12 @@ case $COMPILER in
     echo "CCOMPILERCXX=\"g++\"" >> ./conf/config.sh
     ;;
 
+  "gcc8" )
+    time sudo apt-get install -y gcc-8 g++-8
+    echo "CCOMPILERC=\"gcc-8\"" >> ./conf/config.sh
+    echo "CCOMPILERCXX=\"g++-8\"" >> ./conf/config.sh
+    ;;
+
   "gcc10" )
     time sudo apt-get install -y gcc-10 g++-10
     echo "CCOMPILERC=\"gcc-10\"" >> ./conf/config.sh
diff --git a/apps/ci/ci-install.sh b/apps/ci/ci-install.sh
index 99f267c50..3ad34c6c5 100644
--- a/apps/ci/ci-install.sh
+++ b/apps/ci/ci-install.sh
@@ -33,6 +33,12 @@ case $COMPILER in
     echo "CCOMPILERCXX=\"g++\"" >> ./conf/config.sh
     ;;
 
+  "gcc8" )
+    time sudo apt-get install -y gcc-8 g++-8
+    echo "CCOMPILERC=\"gcc-8\"" >> ./conf/config.sh
+    echo "CCOMPILERCXX=\"g++-8\"" >> ./conf/config.sh
+    ;;
+
   "gcc10" )
     time sudo apt-get install -y gcc-10 g++-10
     echo "CCOMPILERC=\"gcc-10\"" >> ./conf/config.sh