diff --git a/.ci/install.cppcheck b/.ci/install.cppcheck
index 5717cec957..d0f39d13fe 100755
--- a/.ci/install.cppcheck
+++ b/.ci/install.cppcheck
@@ -17,12 +17,12 @@ else
 fi
 
 # pick native architecture
-native="$($CC -march=native -Q --help=target | grep march= | awk '{print $2}')"
+native="$($CC -march=native -Q --help=target | grep "^ *\-march" | awk '{print $2}' | head -n 1)"
 # this is required so that when running the job on a different architecture ccache understand
 # the object file should not be recycled
 
 git checkout $version
-make -j 4 install MATCHCOMPILER=yes FILESDIR="$HOME/opt/share/cppcheck" HAVE_RULES=yes CXXFLAGS="-DNDEBUG -O2 -march="$native" -mtune="$native" -Wall -Wno-sign-compare -Wno-unused-function" PREFIX="$HOME/opt"
+make -j 4 install MATCHCOMPILER=yes FILESDIR="$HOME/opt/share/cppcheck" HAVE_RULES=yes CXXFLAGS="-DNDEBUG -O2 -march=$native -mtune=$native -Wall -Wno-sign-compare -Wno-unused-function" PREFIX="$HOME/opt"
 cd ../
 
 cppcheck --version
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index ab38e60f59..4b3d944acd 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -178,7 +178,7 @@ jobs:
          .ci/push doc
 
   codecheck:
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-20.04
     steps:
     - uses: actions/checkout@v2
     - name: Set path
@@ -225,7 +225,7 @@ jobs:
         make -C docker rocky8
 
   macports:
-    runs-on: macos-10.15
+    runs-on: macos-11
     strategy:
       fail-fast: false
       matrix:
@@ -267,6 +267,7 @@ jobs:
         done
 
   macsimple:
+    # still needs some fix to be upgraded to macos-11
     runs-on: macos-10.15
     steps:
     - uses: actions/checkout@v2
@@ -294,7 +295,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-20.04 , macos-10.15]
+        os: [ubuntu-20.04 , macos-11]
     runs-on: ${{ matrix.os }}
     steps:
     - uses: actions/checkout@v2
diff --git a/regtest/mapping/rt-adapt/config b/regtest/mapping/rt-adapt/config
index 8e7d2bde8a..a3f5190a34 100755
--- a/regtest/mapping/rt-adapt/config
+++ b/regtest/mapping/rt-adapt/config
@@ -5,9 +5,10 @@ arg="--noatoms --plumed plumed.dat"
 function plumed_custom_skip() {
   if [ "$(uname)" = Darwin ] ; then
     fullversion=$(sw_vers -productVersion)
-    fullversion=${fullversion#*.}
-    fullversion=${fullversion%.*}
-    if (( fullversion>14 )) ; then
+    version1=${fullversion%%.*}
+    version2=${fullversion#*.}
+    version2=${version2%%.*}
+    if (( ( version1==10 && version2>14 ) || version1>10)) ; then
       return 0
     fi
   fi