diff --git a/.devcontainer/Dockerfile b/.devcontainer/Dockerfile
index b36d0c51..d4d64e40 100644
--- a/.devcontainer/Dockerfile
+++ b/.devcontainer/Dockerfile
@@ -13,7 +13,8 @@ RUN add-apt-repository -yn 'deb http://archive.ubuntu.com/ubuntu/ trusty main' &
   add-apt-repository -yn 'deb http://apt.llvm.org/bionic/ llvm-toolchain-bionic-6.0 main' && \
   add-apt-repository -yn 'deb http://apt.llvm.org/bionic/ llvm-toolchain-bionic-7 main' && \
   add-apt-repository -yn 'deb http://apt.llvm.org/bionic/ llvm-toolchain-bionic-8 main' && \
-  add-apt-repository -yn 'deb http://apt.llvm.org/bionic/ llvm-toolchain-bionic-9 main'
+  add-apt-repository -yn 'deb http://apt.llvm.org/bionic/ llvm-toolchain-bionic-9 main' && \
+  add-apt-repository -yn 'deb http://mirrors.kernel.org/ubuntu hirsute main universe'
 
 RUN apt-get update && apt-get -y install \
   cmake \
@@ -30,6 +31,7 @@ RUN apt-get update && apt-get -y install \
   g++-8 \
   g++-9 \
   g++-10 \
+  g++-11 \
   clang-3.5 \
   clang-3.6 \
   clang-3.7 \
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 92176182..f708084e 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -40,6 +40,7 @@ jobs:
           - gcc: "9"
             cxxflags: -fsanitize=address -fno-sanitize-recover=all
           - gcc: "10"
+          - gcc: "11"
     steps:
       - name: Install
         run: |
@@ -49,6 +50,7 @@ jobs:
           sudo add-apt-repository -yn 'deb http://archive.ubuntu.com/ubuntu/ xenial universe' 
           sudo add-apt-repository -yn 'deb http://archive.ubuntu.com/ubuntu/ bionic main'
           sudo add-apt-repository -yn 'deb http://archive.ubuntu.com/ubuntu/ bionic universe' 
+          sudo add-apt-repository -yn 'deb http://mirrors.kernel.org/ubuntu hirsute main universe' 
           sudo apt-get update
           sudo apt-get install -y gcc-${{ matrix.gcc }} g++-${{ matrix.gcc }}
       - name: Checkout
diff --git a/README.md b/README.md
index a9dfbc7f..a86ced46 100644
--- a/README.md
+++ b/README.md
@@ -78,7 +78,7 @@ ArduinoJson is a C++ JSON library for Arduino and IoT (Internet Of Things).
     * [Unit test coverage close to 100%](https://coveralls.io/github/bblanchon/ArduinoJson?branch=6.x)
     * Continuously tested on
         * [Visual Studio 2010, 2012, 2013, 2015, 2017, 2019](https://ci.appveyor.com/project/bblanchon/arduinojson/branch/6.x)
-        * [GCC 4.4, 4.6, 4.7, 4.8, 4.9, 5, 6, 7, 8, 9, 10](https://github.com/bblanchon/ArduinoJson/actions?query=workflow%3A%22Continuous+Integration%22)
+        * [GCC 4.4, 4.6, 4.7, 4.8, 4.9, 5, 6, 7, 8, 9, 10, 11](https://github.com/bblanchon/ArduinoJson/actions?query=workflow%3A%22Continuous+Integration%22)
         * [Clang 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 5.0, 6.0, 7, 8, 9, 10](https://github.com/bblanchon/ArduinoJson/actions?query=workflow%3A%22Continuous+Integration%22)
     * [Continuously fuzzed with Google OSS Fuzz](https://bugs.chromium.org/p/oss-fuzz/issues/list?sort=-opened&can=1&q=proj:arduinojson)
     * Passes all default checks of [clang-tidy](https://releases.llvm.org/10.0.0/tools/clang/tools/extra/docs/clang-tidy/)