Deprecated ubuntu 18.04

Author: ymd-stella

docs/docker.rst

@@ -13,7 +13,7 @@ Instructions for PangolinViewer
 ``Dockerfile.desktop`` can be used for easy installation.
 This chapter provides instructions on building and running examples with PangolinViewer support using Docker.
 
-The instructions are tested on Ubuntu 18.04 and 20.04.
+The instructions are tested on Ubuntu 20.04.
 Docker for Mac are NOT supported due to OpenGL forwarding.
 
 .. NOTE ::

docs/installation.rst

@@ -105,7 +105,7 @@ Prerequisites for Unix
 Installing for Linux
 ^^^^^^^^^^^^^^^^^^^^
 
-Tested for **Ubuntu 18.04**.
+Tested for **Ubuntu 20.04**.
 
 Install the dependencies via ``apt``.
 
@@ -341,11 +341,11 @@ Download, build and install backward-cpp.
 | (**if you plan on using SocketViewer**)
 | Install Protobuf.
 
-If you use Ubuntu 18.04 or macOS, Protobuf 3.x can be installed via ``apt`` or ``brew``.
+If you use Ubuntu 20.04 (or later) or macOS, Protobuf 3.x can be installed via ``apt`` or ``brew``.
 
 .. code-block:: bash
 
-    # for Ubuntu 18.04 (or later)
+    # for Ubuntu
     apt install -y libprotobuf-dev protobuf-compiler
     # for macOS
     brew install protobuf

docs/ros_package.rst

@@ -12,7 +12,7 @@ Installation
 Requirements
 ^^^^^^^^^^^^
 
-* `ROS <http://wiki.ros.org/>`_ : ``noetic`` is recommended. (If you have built OpenCV (3.3.1 or later) manually, you can use ``melodic`` or later.)
+* `ROS <http://wiki.ros.org/>`_ : ``noetic``
 
 * :ref:`stella_vslam <chapter-installation>`
 
@@ -25,7 +25,7 @@ Requirements
 Prerequisites
 ^^^^^^^^^^^^^
 
-Tested for **Ubuntu 18.04**.
+Tested for **Ubuntu 20.04**.
 
 Please install the following dependencies.