diff --git a/doc/getting_started/index.rst b/doc/getting_started/index.rst
index 5c09d6522f3..70b241b9fe2 100644
--- a/doc/getting_started/index.rst
+++ b/doc/getting_started/index.rst
@@ -62,7 +62,7 @@ The current minimum required version for the main dependencies are:
      - Min. Version
 
    * - `CMake <https://cmake.org/>`_
-     - 3.13.1
+     - 3.20.0
 
    * - `Python <https://www.python.org/>`_
      - 3.6
@@ -76,6 +76,16 @@ The current minimum required version for the main dependencies are:
 
       .. _install_dependencies_ubuntu:
 
+      #. Download, inspect and execute the Kitware archive script to add the
+         Kitware APT repository to your sources list.
+         A detailed explanation of ``kitware-archive.sh`` can be found here
+         `kitware third-party apt repository <https://apt.kitware.com/>`_::
+
+         .. code-block:: bash
+
+            wget https://apt.kitware.com/kitware-archive.sh
+            sudo bash kitware-archive.sh
+
       #. Use ``apt`` to install the required dependencies:
 
          .. code-block:: bash
diff --git a/doc/getting_started/installation_linux.rst b/doc/getting_started/installation_linux.rst
index 6a4b0ef6bd5..998afe04bed 100644
--- a/doc/getting_started/installation_linux.rst
+++ b/doc/getting_started/installation_linux.rst
@@ -139,9 +139,9 @@ there are several ways of obtaining a more recent one:
   .. code-block:: console
 
      cd ~
-     wget https://github.com/Kitware/CMake/releases/download/v3.15.3/cmake-3.15.3-Linux-x86_64.sh
-     chmod +x cmake-3.15.3-Linux-x86_64.sh
-     sudo ./cmake-3.15.3-Linux-x86_64.sh --skip-license --prefix=/usr/local
+     wget https://github.com/Kitware/CMake/releases/download/v3.21.1/cmake-3.21.1-Linux-x86_64.sh
+     chmod +x cmake-3.21.1-Linux-x86_64.sh
+     sudo ./cmake-3.21.1-Linux-x86_64.sh --skip-license --prefix=/usr/local
      hash -r
 
   The ``hash -r`` command may be necessary if the installation script
@@ -149,14 +149,14 @@ there are several ways of obtaining a more recent one:
 
 * Download and install from the pre-built binaries provided by the CMake
   project itself in the `CMake Downloads`_ page.
-  For example, to install version 3.13.1 in :file:`~/bin/cmake`:
+  For example, to install version 3.21.1 in :file:`~/bin/cmake`:
 
   .. code-block:: console
 
      mkdir $HOME/bin/cmake && cd $HOME/bin/cmake
-     wget https://github.com/Kitware/CMake/releases/download/v3.13.1/cmake-3.13.1-Linux-x86_64.sh
-     yes | sh cmake-3.13.1-Linux-x86_64.sh | cat
-     echo "export PATH=$PWD/cmake-3.13.1-Linux-x86_64/bin:\$PATH" >> $HOME/.zephyrrc
+     wget https://github.com/Kitware/CMake/releases/download/v3.21.1/cmake-3.21.1-Linux-x86_64.sh
+     yes | sh cmake-3.21.1-Linux-x86_64.sh | cat
+     echo "export PATH=$PWD/cmake-3.21.1-Linux-x86_64/bin:\$PATH" >> $HOME/.zephyrrc
 
 * Use ``pip3``: