diff --git a/.github/workflows/ubuntu_install.yml b/.github/workflows/ubuntu_install.yml
index 7bce37fb9..f3108b241 100644
--- a/.github/workflows/ubuntu_install.yml
+++ b/.github/workflows/ubuntu_install.yml
@@ -26,8 +26,7 @@ jobs:
     strategy:
       matrix:
         include:
-          - {shared: ON}
-          - {shared: OFF}
+          shared: [ON, OFF]
     steps:
       - uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4.1.7
       - name: Setup Ninja
diff --git a/.github/workflows/ubuntu_old.yml b/.github/workflows/ubuntu_old.yml
index 8447b29fd..96d330474 100644
--- a/.github/workflows/ubuntu_old.yml
+++ b/.github/workflows/ubuntu_old.yml
@@ -21,12 +21,12 @@ concurrency:
   cancel-in-progress: true
 
 jobs:
-  ubuntu-build:
+  ubuntu-build-20-04:
     runs-on: ubuntu-20.04
     strategy:
       matrix:
         shared: [ON, OFF]
-        cxx: [g++-9, clang++-10]
+        cxx: [g++-10, clang++-10]
     steps:
       - uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4.1.7
       - name: Setup Ninja
diff --git a/README.md b/README.md
index ed1a0b902..5f0c75d7e 100644
--- a/README.md
+++ b/README.md
@@ -28,7 +28,7 @@ standard libraries, follow the RFC 3986. The following table illustrates possibl
 ### Requirements
 
 The project is otherwise self-contained and it has no dependency.
-A recent C++ compiler supporting C++20. We test GCC 9 or better, LLVM 10 or better and Microsoft Visual Studio 2022.
+A recent C++ compiler supporting C++20. We test GCC 12 or better, LLVM 10 or better and Microsoft Visual Studio 2022.
 
 ## Ada is fast.