diff --git a/.github/workflows/CICD.yml b/.github/workflows/CICD.yml
index cd16050..c632cb0 100644
--- a/.github/workflows/CICD.yml
+++ b/.github/workflows/CICD.yml
@@ -16,7 +16,7 @@ on:
 jobs:
   min_version:
     name: Minimum supported rust version
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-20.04
     steps:
     - name: Checkout source code
       uses: actions/checkout@v2
@@ -52,13 +52,6 @@ jobs:
           - { os: ubuntu-20.04, target: i686-unknown-linux-musl     , use-cross: true }
           - { os: ubuntu-20.04, target: x86_64-unknown-linux-gnu    }
           - { os: ubuntu-20.04, target: x86_64-unknown-linux-musl   , use-cross: true }
-          - { os: ubuntu-18.04, target: arm-unknown-linux-gnueabihf , use-cross: true }
-          - { os: ubuntu-18.04, target: arm-unknown-linux-musleabihf, use-cross: true }
-          - { os: ubuntu-18.04, target: aarch64-unknown-linux-gnu   , use-cross: true }
-          - { os: ubuntu-18.04, target: i686-unknown-linux-gnu      , use-cross: true }
-          - { os: ubuntu-18.04, target: i686-unknown-linux-musl     , use-cross: true }
-          - { os: ubuntu-18.04, target: x86_64-unknown-linux-gnu    }
-          - { os: ubuntu-18.04, target: x86_64-unknown-linux-musl   , use-cross: true }
           - { os: macos-10.15 , target: x86_64-apple-darwin         }
           # - { os: windows-2019, target: i686-pc-windows-gnu         }  ## disabled; error: linker `i686-w64-mingw32-gcc` not found
           - { os: windows-2019, target: i686-pc-windows-msvc        }