message: docs: how to get old versions of ckb
diff: We will publish binaries for each release via [Github Releases](https://github.com/nervosnetwork/ckb/releases). If your system
  is listed there, you can download the package directory.
  +There is also a repository [ckb-nightly](https://github.com/nervosnetwork/ckb-nightly/releases) containing the nightly builds from the develop
  +branch.
  +
  ## Build from Source
  @@ -41,7 +44,11 @@ sudo pacman -Sy git gcc pkgconf clang
  brew install autoconf libtool
  ```
  -### Build from master branch
  +### Build from source
  +
  +The `master` branch is regularly built and tested. It is always the latest released version. The default checked out branch `develop` is the latest version in development.
  +
  +It is recommended to build a version from master.
  ```bash
  # get ckb source code
  @@ -56,8 +63,15 @@ make build
  This will build the executable `target/release/ckb`. Please add the directory
  to `PATH` or copy/link the file into a directory already in the `PATH`.
  -```base
  +```bash
  export PATH="$(pwd)/target/release:$PATH"
  # or
  # ln -snf "$(pwd)/target/release/ckb" /usr/local/bin/ckb
  ```
  +
  +It is easy to switch to a history version and build, for example, check out
  +v0.8.0:
  +
  +```bash
  +git checkout -b branch-v0.8.0 v0.8.0
  +```
  