diff --git a/AUTHORS.txt b/AUTHORS.txt
index 5c740f80db..b8e9ea68d3 100644
--- a/AUTHORS.txt
+++ b/AUTHORS.txt
@@ -1,6 +1,6 @@
 * Copyright (C) 1992-2015 Jean-Pierre Charras
-* Copyright (C) 1992-2019 Kicad Developers Team
-* under GNU General Public License (see copyright.txt)
+* Copyright (C) 1992-2021 KiCad Developers Team
+* under GNU General Public License (see LICENSE.README)
 
 == Main Authors
 Jean-Pierre Charras <jean-pierre.charras[at]wanadoo-dot-fr>
diff --git a/INSTALL.txt b/INSTALL.txt
index a22f3d78d4..1afe8acce7 100644
--- a/INSTALL.txt
+++ b/INSTALL.txt
@@ -8,7 +8,7 @@ The parts of KiCad
 
   kicad         - KiCad programs and core files.
   kicad-doc     - Documentation and interactive help (optional package).
-  kicad-library - KiCad schematic, pcb & 3D-model libraries (optional package).
+  kicad-library - Schematic symbol, PCB footprint, and 3D model libraries (optional package).
 
   This repository contains the source code for the main KiCad programs. The documentation
   and library sources are available at https://gitlab.com/kicad
@@ -17,11 +17,11 @@ The parts of KiCad
 Installation from binary packages
 ---------------------------------
 
- Compiled KiCad binaries exist for Windows (7, 8.1, 10), Mac OS (10.12+) and several
- Linux distributions (Fedora, Debian, Ubuntu, Arch). These are available from the
- main KiCad website: https://kicad.org/download/
+  Compiled KiCad binaries exist for Windows (8.1, 10), macOS (10.14+), and several
+  Linux distributions (Fedora, Debian, Ubuntu, Arch). These are available from the
+  main KiCad website: https://kicad.org/download/
 
- Data files (schematic, boards, libraries) are compatible with all platforms.
+  Data files (schematics, boards, libraries) are compatible with all platforms.
 
 
 Installation from binary packages for Windows
@@ -44,34 +44,34 @@ Linux install tree
 
   The default locations KiCad uses to install its components on Linux are:
 
-  ${prefix}/bin                            - Binaries (executable files).
-  ${prefix}/lib/kicad                      - Shared libraries
-  ${prefix}/share/doc/kicad/               - Various documentation.
-  ${prefix}/share/doc/kicad/help           - Interactive help.
-  ${prefix}/share/kicad/demos              - Sample schematics and printed boards.
-  ${prefix}/share/kicad/template           - Template projects and sheets.
-  ${prefix}/share/kicad/library            - Symbol libraries.
-  ${prefix}/share/kicad/modules            - Module libraries for printed boards.
-  ${prefix}/share/kicad/modules/packages3d - 3D component models (.wrl and .step format).
-  ${prefix}/share/kicad/resources          - Resource files (images, etc).
+  ${prefix}/bin                    - Binaries (executable files).
+  ${prefix}/lib/kicad              - Shared libraries.
+  ${prefix}/share/doc/kicad        - Various documentation.
+  ${prefix}/share/doc/kicad/help   - Interactive help.
+  ${prefix}/share/kicad/demos      - Sample schematics and printed boards.
+  ${prefix}/share/kicad/template   - Template projects and sheets.
+  ${prefix}/share/kicad/library    - Schematic symbol libraries.
+  ${prefix}/share/kicad/modules    - PCB footprint libraries.
+  ${prefix}/share/kicad/3dmodels   - 3D component models (.wrl and .step format).
+  ${prefix}/share/kicad/resources  - Resource files (images, etc).
 
   Warning:
   Do not change the KiCad tree, or the location of binary files.  Otherwise
   KiCad may not be able to find some or all of its required files.
 
 
-Mac OS X KiCad tree
--------------------
+macOS KiCad tree
+----------------
 
   System wide files
 
-  /Library/Application Support/kicad/demos
-  /Library/Application Support/kicad/internat
+  /Library/Application Support/kicad/help
+  /Library/Application Support/kicad/template
   /Library/Application Support/kicad/library
   /Library/Application Support/kicad/modules
-  /Library/Application Support/kicad/modules/packages3d
+  /Library/Application Support/kicad/3dmodels
 
-  User files can be the same as the system wide files but only inside the users home directory.
+  User files can be the same as the system wide files but only inside the user's home directory.
 
   $HOME/Library/Application Support/kicad
 
@@ -83,15 +83,15 @@ Mac OS X KiCad tree
 Installation from source code
 -----------------------------
 
-  Currently the only supported compilers are GCC on linux and windows and clang on OS X.
+  Currently the only supported compilers are GCC on Linux and Windows and Clang on macOS.
 
   Some dependencies must be satisfied for the correct installation of KiCad:
 
   wxWidgets            >= 3.0.0           http://www.wxwidgets.org/
 
-  CMake                >= 3.0.2           http://www.cmake.org/
+  CMake                >= 3.10.0          https://www.cmake.org/
 
-  Boost C++ Libraries: >= 1.59            http://www.boost.org/
+  Boost C++ Libraries  >= 1.59            https://www.boost.org/
 
   OpenGL               >= 2.1
     Linux:   Mesa 3D Graphics Library     http://www.mesa3d.org/
@@ -113,7 +113,7 @@ Installation from source code
 
   Doxygen              (optional)         http://www.doxygen.nl
 
-  python               >= 2.6 (optional)  http://python.org/
+  Python               >= 2.6 (optional)  https://python.org/
 
   wxPython             (optional)         http://www.wxpython.org/
 
@@ -126,18 +126,16 @@ Installation from source code
 
     OCC                >= 6.9.0 (optiona) https://www.opencascade.com/content/latest-release
 
-  Complete documentation for building from source can be found in the developer
-  documentation located in Documentation/development/compiling.md
+  Complete documentation for building from source can be found at: https://dev-docs.kicad.org/
 
 
-Important parameters to cmake
+Important parameters to CMake
 -----------------------------
 
-  See Documentation/development/compiling.md for a list of all CMake options
-  available when compiling KiCad.
+  See https://dev-docs.kicad.org/en/build/compile-options/ for a list of all compile options.
 
   -DCMAKE_BUILD_TYPE=<buildtype>
-  <buildtype> may current one of "Debug" and "Release".
+  <buildtype> may be one of "Debug", "Release", or "RelWithDebInfo".
 
   -DCMAKE_INSTALL_PREFIX=<prefix>
   Default to "/usr/local".
@@ -149,7 +147,7 @@ Important parameters to cmake
   Can be used only with -DCMAKE_BUILD_TYPE=Debug
 
   -DCMAKE_CXX_FLAGS=<some extra flags>
-  Extra flags for the c++ compiler for your system required.
+  Extra flags for the C++ compiler required for your system.
 
   -DCMAKE_VERBOSE_MAKEFILE=ON
   When more output is wanted use this cmake parameter or call "make VERBOSE=1".
@@ -163,5 +161,3 @@ Extra CFLAGS and linker flags
       "CXXFLAGS" (c++ compiler)
       "LDFLAGS"  (for linker)
       "CFLAGS"   (for c-compiler, not needed in kdesvn build)
-
-    eg., it may usefull on 64bit systems "-m64" to CXXFLAGS and LDFLAGS.
diff --git a/LICENSE.README b/LICENSE.README
index 59cafbe872..59a8950034 100644
--- a/LICENSE.README
+++ b/LICENSE.README
@@ -1,6 +1,6 @@
 The majority of KiCad's source code is developed and distributed under the terms
-of the GPLv3 or later. However, It does include some third-party code licensed
-under licensed under the BOOST license v1.0, the ISC license and the MIT license.
+of the GPLv3 or later. However, it does include some third-party code licensed
+under other licenses (see below for details).
 
 These licenses are compatible, but a combined works as is will be governed under
 the terms of the GPLv3 (or later). This includes any binary distribution of the
@@ -28,7 +28,7 @@ Licensed under ZLib:
 - nanosvg in thirdparty/nanosvg
 Licensed in the public domain:
 - lemon in thirdparty/lemon
-Licensed under CC-BY-SA-4.0:
+Licensed under CC BY-SA 4.0:
 - All the demo files provided in demos/*
 Licensed under GPLv3 (or later):
 - All remaining code not listed above
diff --git a/README.md b/README.md
index 09efe1d0ff..e1a289f97a 100644
--- a/README.md
+++ b/README.md
@@ -33,7 +33,7 @@ libraries, see our [Website](https://kicad.org/) and our [Forum](https://forum.k
 ## Subdirectories
 
 * [3d-viewer](3d-viewer)         - Sourcecode of the 3D viewer
-* [bitmap2component](bitmap2component)  - Sourcecode of the bitmap to pcb artwork converter
+* [bitmap2component](bitmap2component)  - Sourcecode of the bitmap to PCB artwork converter
 * [bitmaps_png](bitmaps_png)       - Menu and program icons
 * [CMakeModules](CMakeModules)      - Modules for the CMAKE build tool
 * [common](common)            - Sourcecode of the common library
@@ -45,18 +45,17 @@ libraries, see our [Website](https://kicad.org/) and our [Forum](https://forum.k
 * [helpers](helpers)           - Helper tools and utilities for development
 * [include](include)           - Interfaces to the common library
 * [kicad](kicad)             - Sourcecode of the project manager
-* [libs](libs)           - Sourcecode of kicad utilities (geometry and others)
+* [libs](libs)           - Sourcecode of KiCad utilities (geometry and others)
 * [pagelayout_editor](pagelayout_editor) - Sourcecode of the pagelayout editor
 * [patches](patches)           - Collection of patches for external dependencies
 * [pcbnew](pcbnew)           - Sourcecode of the printed circuit board editor
-* [plugins](plugins)           - Sourcecode for the 3d viewer plugins
+* [plugins](plugins)           - Sourcecode for the 3D viewer plugins
 * [qa](qa)                - Unit testing framework for KiCad
 * [resources](resources)         - Packaging resources for various operating systems
 * [scripting](scripting)         - SWIG Python scripting definitions and build scripts
 * [scripts](scripts)           - Example scripts for distribution with KiCad
 * [template](template)          - Project template
-* [thirdparty](thirdparty)           - Sourcecode of external libraries used in kicad but not written by Kicad team
+* [thirdparty](thirdparty)           - Sourcecode of external libraries used in KiCad but not written by the KiCad team
 * [tools](tools)             - Other miscellaneous helpers for testing
 * [translation](translation) - Translation data files (managed through [Weblate](https://hosted.weblate.org/projects/kicad/master-source/) for most languages)
-* [utils](utils)             - Small utils for kicad, e.g. IDF, STEP and OGL tools and converters
-
+* [utils](utils)             - Small utils for KiCad, e.g. IDF, STEP, and OGL tools and converters