diff --git a/README.md b/README.md
index 5cf1d5a..d87b05f 100644
--- a/README.md
+++ b/README.md
@@ -55,58 +55,25 @@ A minimal, sidebar, responsive web design Jekyll theme that focuses on text pres
 
 ## Prerequisites
 
-Follow the [Jekyll Docs](https://jekyllrb.com/docs/installation/) to complete the installation of `Ruby`, `RubyGems`, `Jekyll` and `Bundler`. Please note that the version of `Ruby` must meet the requirements of the theme on [RubyGems.org](https://rubygems.org/gems/jekyll-theme-chirpy).
+Follow the instructions in the [Jekyll Docs](https://jekyllrb.com/docs/installation/) to complete the installation of `Ruby`, `RubyGems`, `Jekyll` and `Bundler`.
 
 ## Installation
 
-There are two ways to get the theme:
+### Creating a New Site
 
-- **[Install from RubyGems](#install-from-rubygems)** - Easy to update, isolate irrelevant project files so you can focus on writing.
-- **[Fork on GitHub](#fork-on-github)** - Convenient for custom development, but difficult to update, only suitable for web developers.
+There are two ways to create a new repository for this theme:
 
-### Install from RubyGems
+- **[Using the Chirpy Starter](#option-1-using-the-chirpy-starter)** - Easy to upgrade, isolates irrelevant project files so you can focus on writing.
 
-Add this line to your Jekyll site's `Gemfile`:
+- **[Forking on GitHub](#option-2-forking-on-github)** - Convenient for custom development, but difficult to upgrade. Unless you are familiar with Jekyll and are determined to tweak or contribute to this project, this approach is not recommended.
 
-```ruby
-gem "jekyll-theme-chirpy"
-```
+#### Option 1. Using the Chirpy Starter
 
-And add this line to your Jekyll site's `_config.yml`:
+Create a new repository from the [**Chirpy Starter**][use-starter] and name it `<GH_USERNAME>.github.io`, where `GH_USERNAME` represents your GitHub username.
 
-```yaml
-theme: jekyll-theme-chirpy
-```
+#### Option 2. Forking on GitHub
 
-And then execute:
-
-```console
-$ bundle
-```
-
-Next, go to the installed local theme path:
-
-```console
-$ cd "$(bundle info --path jekyll-theme-chirpy)"
-```
-
-And then copy the critical files (for details, see [starter project][starter]) from the theme's gem to your Jekyll site.
-
-> ⚠️ **Watch out for duplicate files!**
->
-> If your Jekyll site is created by the `jekyll new` command, there will be `index.markdown` and `about.markdown` in the root directory of your site. Please be sure to remove them, otherwise they will overwrite the `index.html` and `_tabs/about.html` from this project, resulting in blank or messy pages.
-
-As an alternative, which we recommend, you can create a Jekyll site [**using the starter template**][use-starter] to save time copying files from the theme's gem. We've prepared everything you need there!
-
-### Fork on GitHub
-
-[Fork **Chirpy**](https://github.com/cotes2020/jekyll-theme-chirpy/fork) on GitHub and then clone your fork to local. (Please note that the default branch code is in development.  If you want the blog to be stable, please switch to the [latest tag](https://github.com/cotes2020/jekyll-theme-chirpy/tags) and start writing.)
-
-Install gem dependencies by:
-
-```console
-$ bundle
-```
+[Fork **Chirpy**](https://github.com/cotes2020/jekyll-theme-chirpy/fork) on GitHub and rename it to `<GH_USERNAME>.github.io`. Please note that the default branch code is in development.  If you want the site to be stable, please switch to the [latest tag](https://github.com/cotes2020/jekyll-theme-chirpy/tags) and start writing.
 
 And then execute:
 
@@ -114,18 +81,28 @@ And then execute:
 $ bash tools/init.sh
 ```
 
-> **Note**: If you don't plan to deploy your site on GitHub Pages, append parameter option `--no-gh` at the end of the above command.
+> **Note**: If you don't want to deploy your site on GitHub Pages, append option `--no-gh` at the end of the above command.
 
-What it does is:
+The above command will:
 
-1. Remove some files or directories from your repository:
+1. Removes some files or directories from your repository:
     - `.travis.yml`
     - files under `_posts`
     - folder `docs`
 
-2. If you use the `--no-gh` option, the directory `.github` will be deleted. Otherwise, setup the GitHub Action workflow by removing the extension `.hook` of `.github/workflows/pages-deploy.yml.hook`, and then remove the other files and directories in the folder `.github`.
+2. If the option `--no-gh` is provided, the directory `.github` will be deleted. Otherwise, setup the GitHub Action workflow by removing the extension `.hook` of `.github/workflows/pages-deploy.yml.hook`, and then remove the other files and directories in the folder `.github`.
 
-3. Automatically create a commit to save the changes.
+3. Removes item `Gemfile.lock` from `.gitignore`.
+
+4. Creates a new commit to save the changes automatically.
+
+### Installing Dependencies
+
+Before running for the first time, go the root directory of your site, and install dependencies as follows:
+
+```console
+$ bundle
+```
 
 ## Usage
 
@@ -142,7 +119,7 @@ Update the variables of `_config.yml` as needed. Some of them are typical option
 
 If you need to customize stylesheet, copy the theme's `assets/css/style.scss` to the same path on your Jekyll site, and then add the custom style at the end of the style file.
 
-Starting from `v4.1.0`, if you want to overwrite the SASS variables defined in `_sass/addon/variables.scss`, create a new file `_sass/variables-hook.scss` and assign new values to the target variable in it.
+Starting from [`v4.1.0`][chirpy-4.1.0], if you want to overwrite the SASS variables defined in `_sass/addon/variables.scss`, create a new file `_sass/variables-hook.scss` and assign new values to the target variable in it.
 
 ### Running Local Server
 
@@ -154,14 +131,14 @@ $ bundle exec jekyll s
 
 Or run the site on Docker with the following command:
 
-```terminal
+```console
 $ docker run -it --rm \
     --volume="$PWD:/srv/jekyll" \
     -p 4000:4000 jekyll/jekyll \
     jekyll serve
 ```
 
-Open a browser and visit to _<http://localhost:4000>_.
+After a while, the local service will be published at _<http://127.0.0.1:4000>_.
 
 ### Deployment
 
@@ -169,40 +146,47 @@ Before the deployment begins, checkout the file `_config.yml` and make sure the
 
 Now you can choose ONE of the following methods to deploy your Jekyll site.
 
-#### Deploy on GitHub Pages
+#### Deploy by Using Github Actions
 
-For security reasons, GitHub Pages build runs on `safe` mode, which restricts us from using plugins to generate additional page files. Therefore, we can use **GitHub Actions** to build the site, store the built site files on a new branch, and use that branch as the source of the GH Pages service.
+For security reasons, GitHub Pages build runs on `safe` mode, which restricts us from using plugins to generate additional page files. Therefore, we can use **GitHub Actions** to build the site, store the built site files on a new branch, and use that branch as the source of the GitHub Pages service.
 
 Quickly check the files needed for GitHub Actions build:
 
-- Ensure your Jekyll site has the file `.github/workflows/pages-deploy.yml`. Otherwise, create a new one and fill in the contents of the [workflow file][workflow], and the value of the `on.push.branches` should be the same as your repo's default branch name.
-- Ensure your Jekyll site has file `tools/test.sh` and `tools/deploy.sh`. Otherwise, copy them from this repo to your Jekyll site.
+- Ensure your Jekyll site has the file `.github/workflows/pages-deploy.yml`. Otherwise, create a new one and fill in the contents of the [sample file][workflow], and the value of the `on.push.branches` should be the same as your repo's default branch name.
 
-And then rename your repository to `<GH-USERNAME>.github.io` on GitHub.
+- Ensure your Jekyll site has file `tools/deploy.sh`. Otherwise, copy it from here to your Jekyll site.
+
+- Furthermore, if you have committed `Gemfile.lock` to the repo, and your runtime system is not Linux, don't forget to update the platform list in the lockfile:
+
+  ```console
+  $ bundle lock --add-platform x86_64-linux
+  ```
+
+After the above steps, rename your repository to `<GH_USERNAME>.github.io` on GitHub.
 
 Now publish your Jekyll site by:
 
 1. Push any commit to remote to trigger the GitHub Actions workflow. Once the build is complete and successful, a new remote branch named `gh-pages` will appear to store the built site files.
 
-2. Browse to your repo's landing page on GitHub and select the branch `gh-pages` as the [publishing source](https://docs.github.com/en/github/working-with-github-pages/configuring-a-publishing-source-for-your-github-pages-site) through _Settings_ → _Options_ → _GitHub Pages_:
+2. Browse to your repository on GitHub. Select the tab _Settings_, then click _Pages_ in the left navigation bar, and then in the section **Source** of _GitHub Pages_, select the `/(root)` directory of branch `gh-pages` as the [publishing source][pages-src]. Remember to click <kbd>Save</kbd> before leaving.
 
     ![gh-pages-sources](https://cdn.jsdelivr.net/gh/cotes2020/chirpy-images/posts/20190809/gh-pages-sources.png)
 
 3. Visit your website at the address indicated by GitHub.
 
-#### Deploy on Other Platforms
+#### Manually Build and Deploy
 
-On platforms other than GitHub, we cannot enjoy the convenience of **GitHub Actions**. Therefore, we should build the site locally (or on some other 3rd-party CI platform) and then put the site files on the server.
+On self-hosted servers, you cannot enjoy the convenience of **GitHub Actions**. Therefore, you should build the site on your local machine and then upload the site files to the server.
 
-Go to the root of the source project, build your site by:
+Go to the root of the source project, and build your site as follows:
 
 ```console
 $ JEKYLL_ENV=production bundle exec jekyll b
 ```
 
-Or build the site with Docker by:
+Or build the site on Docker:
 
-```terminal
+```console
 $ docker run -it --rm \
     --env JEKYLL_ENV=production \
     --volume="$PWD:/srv/jekyll" \
@@ -210,7 +194,28 @@ $ docker run -it --rm \
     jekyll build
 ```
 
-Unless you specified the output path, the generated site files will be placed in folder `_site` of the project's root directory. Now you should upload those files to your web server.
+Unless you specified the output path, the generated site files will be placed in folder `_site` of the project's root directory. Now you should upload those files to the target server.
+
+### Upgrading
+
+It depends on how you use the theme:
+
+- If you are using the theme gem (there will be `gem "jekyll-theme-chirpy"` in the `Gemfile`), editing the `Gemfile` and update the version number of the them gem, for example:
+    ```diff
+    - gem "jekyll-theme-chirpy", "~> 3.2", ">= 3.2.1"
+    + gem "jekyll-theme-chirpy", "~> 3.3", ">= 3.3.0"
+    ```
+
+    And then execute the following command:
+
+    ```console
+    $ bundle update jekyll-theme-chirpy
+    ```
+
+    As the version upgrades, the critical files (for details, see the [Startup Template][starter]) and configuration options will change. Please refer to the [Upgrade Guide](https://github.com/cotes2020/jekyll-theme-chirpy/wiki/Upgrade-Guide) to keep your repo's files in sync with the latest version of the theme.
+
+- If you forked from the source project (there will be `gemspec` in the `Gemfile` of your site), then merge the [latest upstream tags][latest-tag] into your Jekyll site to complete the upgrade.
+The merge is likely to conflict with your local modifications. Please be patient and careful to resolve these conflicts.
 
 ## Documentation
 
@@ -243,6 +248,9 @@ This work is published under [MIT](https://github.com/cotes2020/jekyll-theme-chi
 [starter]: https://github.com/cotes2020/chirpy-starter
 [use-starter]: https://github.com/cotes2020/chirpy-starter/generate
 [workflow]: https://github.com/cotes2020/jekyll-theme-chirpy/blob/master/.github/workflows/pages-deploy.yml.hook
+[chirpy-4.1.0]: https://github.com/cotes2020/jekyll-theme-chirpy/releases/tag/v4.1.0
+[pages-src]: https://docs.github.com/en/github/working-with-github-pages/configuring-a-publishing-source-for-your-github-pages-site
+[latest-tag]: https://github.com/cotes2020/jekyll-theme-chirpy/tags
 
 <!-- ReadMe links -->
 
diff --git a/_posts/2019-08-08-write-a-new-post.md b/_posts/2019-08-08-write-a-new-post.md
index 0a03f96..d001006 100644
--- a/_posts/2019-08-08-write-a-new-post.md
+++ b/_posts/2019-08-08-write-a-new-post.md
@@ -146,7 +146,7 @@ By default, the image is centered, but you can specify the position by using one
   ```
   {: .nolineno}
 
-> **Limitation**: Once you specify the position of an image, it is forbidden to add the image caption.
+> **Limitation**: Once the position of the image is specified, the image caption should not be added.
 
 ### Image shadow
 
diff --git a/_posts/2019-08-09-getting-started.md b/_posts/2019-08-09-getting-started.md
index 2a35dcc..639d0bf 100644
--- a/_posts/2019-08-09-getting-started.md
+++ b/_posts/2019-08-09-getting-started.md
@@ -9,60 +9,25 @@ pin: true
 
 ## Prerequisites
 
-Follow the [Jekyll Docs](https://jekyllrb.com/docs/installation/) to complete the installation of `Ruby`, `RubyGems`, `Jekyll` and `Bundler`. Please note that the version of `Ruby` must meet the requirements of the theme on [RubyGems.org](https://rubygems.org/gems/jekyll-theme-chirpy).
+Follow the instructions in the [Jekyll Docs](https://jekyllrb.com/docs/installation/) to complete the installation of `Ruby`, `RubyGems`, `Jekyll` and `Bundler`.
 
 ## Installation
 
-There are two ways to get the theme:
+### Creating a New Site
 
-- **[Install from RubyGems](#install-from-rubygems)** - Easy to update, isolate irrelevant project files so you can focus on writing.
-- **[Fork on GitHub](#fork-on-github)** - Convenient for custom development, but difficult to update, only suitable for web developers.
+There are two ways to create a new repository for this theme:
 
-### Install from RubyGems
+- **[Using the Chirpy Starter](#option-1-using-the-chirpy-starter)** - Easy to upgrade, isolates irrelevant project files so you can focus on writing.
 
-Add this line to your Jekyll site's `Gemfile`:
+- **[Forking on GitHub](#option-2-forking-on-github)** - Convenient for custom development, but difficult to upgrade. Unless you are familiar with Jekyll and are determined to tweak or contribute to this project, this approach is not recommended.
 
-```ruby
-gem "jekyll-theme-chirpy"
-```
-{: .nolineno file='Gemfile' }
+#### Option 1. Using the Chirpy Starter
 
-And add this line to your Jekyll site's `_config.yml`:
+Create a new repository from the [**Chirpy Starter**][use-starter] and name it `<GH_USERNAME>.github.io`, where `GH_USERNAME` represents your GitHub username.
 
-```yaml
-theme: jekyll-theme-chirpy
-```
-{: .nolineno file='_config.yml' }
+#### Option 2. Forking on GitHub
 
-And then execute:
-
-```console
-$ bundle
-```
-
-Next, go to the installed local theme path:
-
-```console
-$ cd "$(bundle info --path jekyll-theme-chirpy)"
-```
-
-And then copy the critical files (for details, see [starter project][starter]) from the theme's gem to your Jekyll site.
-
-> ⚠️ **Watch out for duplicate files!**
->
-> If your Jekyll site is created by the `jekyll new` command, there will be `index.markdown` and `about.markdown` in the root directory of your site. Please be sure to remove them, otherwise they will overwrite the `index.html` and `_tabs/about.html` from this project, resulting in blank or messy pages.
-
-As an alternative, which we recommend, you can create a Jekyll site [**using the starter template**][use-starter] to save time copying files from the theme's gem. We've prepared everything you need there!
-
-### Fork on GitHub
-
-[Fork **Chirpy**](https://github.com/cotes2020/jekyll-theme-chirpy/fork) on GitHub and then clone your fork to local. (Please note that the default branch code is in development.  If you want the blog to be stable, please switch to the [latest tag](https://github.com/cotes2020/jekyll-theme-chirpy/tags) and start writing.)
-
-Install gem dependencies by:
-
-```console
-$ bundle
-```
+[Fork **Chirpy**](https://github.com/cotes2020/jekyll-theme-chirpy/fork) on GitHub and rename it to `<GH_USERNAME>.github.io`. Please note that the default branch code is in development.  If you want the site to be stable, please switch to the [latest tag][latest-tag] and start writing.
 
 And then execute:
 
@@ -70,18 +35,28 @@ And then execute:
 $ bash tools/init.sh
 ```
 
-> **Note**: If you don't plan to deploy your site on GitHub Pages, append parameter option `--no-gh` at the end of the above command.
+> **Note**: If you don't want to deploy your site on GitHub Pages, append option `--no-gh` at the end of the above command.
 
-What it does is:
+The above command will:
 
-1. Remove some files or directories from your repository:
+1. Removes some files or directories from your repository:
     - `.travis.yml`
     - files under `_posts`
     - folder `docs`
 
-2. If you use the `--no-gh` option, the directory `.github` will be deleted. Otherwise, setup the GitHub Action workflow by removing the extension `.hook` of `.github/workflows/pages-deploy.yml.hook`, and then remove the other files and directories in the folder `.github`.
+2. If the option `--no-gh` is provided, the directory `.github` will be deleted. Otherwise, setup the GitHub Action workflow by removing the extension `.hook` of `.github/workflows/pages-deploy.yml.hook`, and then remove the other files and directories in the folder `.github`.
 
-3. Automatically create a commit to save the changes.
+3. Removes item `Gemfile.lock` from `.gitignore`.
+
+4. Creates a new commit to save the changes automatically.
+
+### Installing Dependencies
+
+Before running for the first time, go the root directory of your site, and install dependencies as follows:
+
+```console
+$ bundle
+```
 
 ## Usage
 
@@ -98,7 +73,7 @@ Update the variables of `_config.yml` as needed. Some of them are typical option
 
 If you need to customize stylesheet, copy the theme's `assets/css/style.scss` to the same path on your Jekyll site, and then add the custom style at the end of the style file.
 
-Starting from `v4.1.0`, if you want to overwrite the SASS variables defined in `_sass/addon/variables.scss`, create a new file `_sass/variables-hook.scss` and assign new values to the target variable in it.
+Starting from [`v4.1.0`][chirpy-4.1.0], if you want to overwrite the SASS variables defined in `_sass/addon/variables.scss`, create a new file `_sass/variables-hook.scss` and assign new values to the target variable in it.
 
 ### Running Local Server
 
@@ -110,14 +85,14 @@ $ bundle exec jekyll s
 
 Or run the site on Docker with the following command:
 
-```terminal
+```console
 $ docker run -it --rm \
     --volume="$PWD:/srv/jekyll" \
     -p 4000:4000 jekyll/jekyll \
     jekyll serve
 ```
 
-Open a browser and visit to _<http://localhost:4000>_.
+After a while, the local service will be published at _<http://127.0.0.1:4000>_.
 
 ### Deployment
 
@@ -125,40 +100,47 @@ Before the deployment begins, checkout the file `_config.yml` and make sure the
 
 Now you can choose ONE of the following methods to deploy your Jekyll site.
 
-#### Deploy on GitHub Pages
+#### Deploy by Using Github Actions
 
-For security reasons, GitHub Pages build runs on `safe` mode, which restricts us from using plugins to generate additional page files. Therefore, we can use **GitHub Actions** to build the site, store the built site files on a new branch, and use that branch as the source of the GH Pages service.
+For security reasons, GitHub Pages build runs on `safe` mode, which restricts us from using plugins to generate additional page files. Therefore, we can use **GitHub Actions** to build the site, store the built site files on a new branch, and use that branch as the source of the GitHub Pages service.
 
 Quickly check the files needed for GitHub Actions build:
 
-- Ensure your Jekyll site has the file `.github/workflows/pages-deploy.yml`. Otherwise, create a new one and fill in the contents of the [workflow file][workflow], and the value of the `on.push.branches` should be the same as your repo's default branch name.
-- Ensure your Jekyll site has file `tools/test.sh` and `tools/deploy.sh`. Otherwise, copy them from this repo to your Jekyll site.
+- Ensure your Jekyll site has the file `.github/workflows/pages-deploy.yml`. Otherwise, create a new one and fill in the contents of the [sample file][workflow], and the value of the `on.push.branches` should be the same as your repo's default branch name.
 
-And then rename your repository to `<GH-USERNAME>.github.io` on GitHub.
+- Ensure your Jekyll site has file `tools/deploy.sh`. Otherwise, copy it from here to your Jekyll site.
+
+- Furthermore, if you have committed `Gemfile.lock` to the repo, and your runtime system is not Linux, don't forget to update the platform list in the lockfile:
+
+  ```console
+  $ bundle lock --add-platform x86_64-linux
+  ```
+
+After the above steps, rename your repository to `<GH_USERNAME>.github.io` on GitHub.
 
 Now publish your Jekyll site by:
 
 1. Push any commit to remote to trigger the GitHub Actions workflow. Once the build is complete and successful, a new remote branch named `gh-pages` will appear to store the built site files.
 
-2. Browse to your repo's landing page on GitHub and select the branch `gh-pages` as the [publishing source](https://docs.github.com/en/github/working-with-github-pages/configuring-a-publishing-source-for-your-github-pages-site) through _Settings_ → _Options_ → _GitHub Pages_:
+2. Browse to your repository on GitHub. Select the tab _Settings_, then click _Pages_ in the left navigation bar, and then in the section **Source** of _GitHub Pages_, select the `/(root)` directory of branch `gh-pages` as the [publishing source][pages-src]. Remember to click <kbd>Save</kbd> before leaving.
 
     ![gh-pages-sources](https://cdn.jsdelivr.net/gh/cotes2020/chirpy-images/posts/20190809/gh-pages-sources.png){: width="850" height="153" }
 
 3. Visit your website at the address indicated by GitHub.
 
-#### Deploy on Other Platforms
+#### Manually Build and Deploy
 
-On platforms other than GitHub, we cannot enjoy the convenience of **GitHub Actions**. Therefore, we should build the site locally (or on some other 3rd-party CI platform) and then put the site files on the server.
+On self-hosted servers, you cannot enjoy the convenience of **GitHub Actions**. Therefore, you should build the site on your local machine and then upload the site files to the server.
 
-Go to the root of the source project, build your site by:
+Go to the root of the source project, and build your site as follows:
 
 ```console
 $ JEKYLL_ENV=production bundle exec jekyll b
 ```
 
-Or build the site with Docker by:
+Or build the site on Docker:
 
-```terminal
+```console
 $ docker run -it --rm \
     --env JEKYLL_ENV=production \
     --volume="$PWD:/srv/jekyll" \
@@ -166,8 +148,34 @@ $ docker run -it --rm \
     jekyll build
 ```
 
-Unless you specified the output path, the generated site files will be placed in folder `_site` of the project's root directory. Now you should upload those files to your web server.
+Unless you specified the output path, the generated site files will be placed in folder `_site` of the project's root directory. Now you should upload those files to the target server.
+
+### Upgrading
+
+It depends on how you use the theme:
+
+- If you are using the theme gem (there will be `gem "jekyll-theme-chirpy"` in the `Gemfile`), editing the `Gemfile` and update the version number of the them gem, for example:
+
+    ```diff
+  - gem "jekyll-theme-chirpy", "~> 3.2", ">= 3.2.1"
+  + gem "jekyll-theme-chirpy", "~> 3.3", ">= 3.3.0"
+    ```
+    {: .nolineno file="Gemfile" }
+
+    And then execute the following command:
+
+    ```console
+    $ bundle update jekyll-theme-chirpy
+    ```
+
+    As the version upgrades, the critical files (for details, see the [Startup Template][starter]) and configuration options will change. Please refer to the [Upgrade Guide](https://github.com/cotes2020/jekyll-theme-chirpy/wiki/Upgrade-Guide) to keep your repo's files in sync with the latest version of the theme.
+
+- If you forked from the source project (there will be `gemspec` in the `Gemfile` of your site), then merge the [latest upstream tags][latest-tag] into your Jekyll site to complete the upgrade.
+The merge is likely to conflict with your local modifications. Please be patient and careful to resolve these conflicts.
 
 [starter]: https://github.com/cotes2020/chirpy-starter
 [use-starter]: https://github.com/cotes2020/chirpy-starter/generate
 [workflow]: https://github.com/cotes2020/jekyll-theme-chirpy/blob/master/.github/workflows/pages-deploy.yml.hook
+[chirpy-4.1.0]: https://github.com/cotes2020/jekyll-theme-chirpy/releases/tag/v4.1.0
+[pages-src]: https://docs.github.com/en/github/working-with-github-pages/configuring-a-publishing-source-for-your-github-pages-site
+[latest-tag]: https://github.com/cotes2020/jekyll-theme-chirpy/tags
diff --git a/_posts/2019-08-11-customize-the-favicon.md b/_posts/2019-08-11-customize-the-favicon.md
index 5f058a3..e6c3c4b 100644
--- a/_posts/2019-08-11-customize-the-favicon.md
+++ b/_posts/2019-08-11-customize-the-favicon.md
@@ -6,7 +6,7 @@ categories: [Blogging, Tutorial]
 tags: [favicon]
 ---
 
-The [favicons](https://www.favicon-generator.org/about/) of [**Chirpy**](https://github.com/cotes2020/jekyll-theme-chirpy/) are placed in the directory `assets/img/favicons/`. You may need to replace them with your own. The following sections will guide you how to create and replace the default favicons.
+The [favicons](https://www.favicon-generator.org/about/) of [**Chirpy**](https://github.com/cotes2020/jekyll-theme-chirpy/) are placed in the directory `assets/img/favicons/`. You may want to replace them with your own. The following sections will guide you how to create and replace the default favicons.
 
 ## Generate the favicon
 
@@ -21,7 +21,7 @@ Download the generated package, unzip and delete the following two from the extr
 - `browserconfig.xml`
 - `site.webmanifest`
 
-Now, copy the remaining image files (`PNG` and `ICO`) to cover the original files in the folder `assets/img/favicons/` of your Jekyll site.
+Now, copy the remaining image files (`PNG` and `ICO`) to cover the original files in the folder `assets/img/favicons/` of your Jekyll site. If your Jekyll site doesn't have this directory yet, just create one.
 
 The following table will helps you understand the changes to the favicon files:
 
diff --git a/docs/README.zh-CN.md b/docs/README.zh-CN.md
index 4c41d60..ab45473 100644
--- a/docs/README.zh-CN.md
+++ b/docs/README.zh-CN.md
@@ -54,62 +54,27 @@
 - SEO 优化
 - 网站性能优化
 
-
 ## 前提要求
 
-参考 [Jekyll Docs](https://jekyllrb.com/docs/installation/) 安装 `Ruby`，`RubyGems`，`Jekyll` 和 `Bundler`。需要注意的是，`Ruby` 的版本必须与主题在 [RubyGems.org](https://rubygems.org/gems/jekyll-theme-chirpy) 上的要求一致.
+参考 [Jekyll Docs](https://jekyllrb.com/docs/installation/) 安装 `Ruby`，`RubyGems`，`Jekyll` 和 `Bundler`。
 
 ## 安装
 
-有二法可得此主题:
+### 创建新仓库
 
-- **[从 RubyGems 安装](#从-rubygems-安装)** - 易于版本升级，隔离无关的主题项目文件，让您的仓库舒适清爽。
-- **[从 GitHub 上 Fork](#从-github-上-fork)** - 对个性化二次开发友好，但是难于升级，只适合专业开发人员使用。
+有两种方式可以创建一个使用本主题的仓库：
 
-### 从 RubyGems 安装
+- **[使用 Chirpy Starter](#使用-chirpy-starter)** - 易于版本升级，隔离无关的主题项目文件，让您的仓库舒适清爽。
 
-在您的 Jekyll 站点的 `Gemfile` 添加:
+- **[从 GitHub 上 Fork](#从-github-上-fork)** - 对个性化二次开发友好，但是难于升级。除非您决定魔改此款主题或者参与代码贡献，否则不推荐使用此方式。
 
-```ruby
-gem "jekyll-theme-chirpy"
-```
+#### 使用 Chirpy Starter
 
-然后，添加这行到您的 Jekyll 站点的 `_config.yml`:
+[使用 Chirpy Starter][use-starter] 来快速创建 Jekyll 站点，命名为 `<GH_USERNAME>.github.io`，其中 `GH_USERNAME` 是您的 GitHub username。
 
-```yaml
-theme: jekyll-theme-chirpy
-```
+#### 从 GitHub 上 Fork
 
-接着执行:
-
-```console
-$ bundle
-```
-
-然后，进入主题的 gem 目录:
-
-```console
-$ cd "$(bundle info --path jekyll-theme-chirpy)"
-```
-
-拷贝运行站点所需主题的 gem 文件（详见 [starter 仓库][starter] 的文件目录）至您的 Jekyll 站点, 然后把主题的 `_config.yml` 全部内容附加到您的 Jekyll 站点的同名文件。
-
-> ⚠️ **留意重叠的文件！**
->
-> 如果您的网站是通过命令 `jekyll new` 创建的，那么站点的根目录会存在文件 `index.markdown` 和 `about.markdown`。 请务必删除它们, 否则在网站构建后将覆盖主题的 `index.html` 和 `_tabs/about.html`，引起空白或错乱的页面出现。
-
-作为替代方案，同时也被我们力荐，您可以 [使用 starter template][use-starter] 来快速创建 Jekyll 站点，以省去复制主题 gem 文件的时间。那里早已为您准备好建站需要的一切！
-
-
-### 从 GitHub 上 Fork
-
-[Fork **Chirpy**](https://github.com/cotes2020/jekyll-theme-chirpy/fork) 然后克隆到本地。(友情提示：默认分支的代码处于开发状态，如果您想博客更加稳定，请切换到最新的 [Tag](https://github.com/cotes2020/jekyll-theme-chirpy/tags) 开始写作。)
-
-安装依赖：
-
-```console
-$ bundle
-```
+[Fork **Chirpy**](https://github.com/cotes2020/jekyll-theme-chirpy/fork) 并改名为 `<GH_USERNAME>.github.io`。友情提示：默认分支的代码处于开发状态，如果您想博客更加稳定，请切换到最新的 [Tag][latest-tag] 开始写作。
 
 接着执行文件初始化:
 
@@ -117,18 +82,28 @@ $ bundle
 $ bash tools/init.sh
 ```
 
-> 如果您不打算部署到 GitHub Pages, 在上述命令后附加参数选项 `--no-gh`。
+> **注**：如果您不打算部署到 GitHub Pages， 在上述命令后附加参数选项 `--no-gh`。
 
-上述脚本完成了以下工作:
+上述脚本将会:
 
 1. 从您的仓库中删除了:
     - `.travis.yml`
     - `_posts` 下的文件
     - `docs` 目录
 
-2. 如果使用了参数 `--no-gh`，则会怒删 `.github`。否则，将会配置 GitHub Actions：把 `.github/workflows/pages-deploy.yml.hook` 的后缀 `.hook` 去除，然后删除 `.github` 里的其他目录和文件。
+2. 如果使用了参数 `--no-gh`，则会怒删文件夹 `.github`。否则，配置 GitHub Actions：把 `.github/workflows/pages-deploy.yml.hook` 的后缀 `.hook` 去除，然后删除 `.github` 里的其他目录和文件。
 
-3. 自动提交一个 Commit 以保存上述文件的更改。
+3. 从 `.gitignore` 中删除 `Gemfile.lock`。
+
+4. 自动提交一个 Commit 以保存上述文件的更改。
+
+### 安装依赖：
+
+首次运行本项目，需要先安装依赖：
+
+```console
+$ bundle
+```
 
 ## 使用
 
@@ -143,9 +118,9 @@ $ bash tools/init.sh
 
 ### 自定义样式
 
-如果您需要自定义样式, 拷贝主题的文件 `assets/css/style.scss` 到您站点的相同路径上，然后在该文件末尾添加样式。
+如果您需要自定义样式， 拷贝主题的文件 `assets/css/style.scss` 到您站点的相同路径上，然后在该文件末尾添加样式。
 
-自 `v4.1.0` 起，如果您想覆盖文件 `_sass/addon/variables.scss` 里定义的 SASS 变量的默认值，新建文件 `_sass/variables-hook.scss`，然后重写您需要的变量即可。
+自 [`v4.1.0`][chirpy-4.1.0] 起，如果您想覆盖文件 `_sass/addon/variables.scss` 里定义的 SASS 变量的默认值，新建文件 `_sass/variables-hook.scss`，然后重写您需要的变量即可。
 
 ### 本地运行
 
@@ -164,36 +139,43 @@ $ docker run -it --rm \
     jekyll serve
 ```
 
-访问本地服务：<http://localhost:4000>
+稍候片刻，即可访问本地服务：_<http://localhost:4000>_
 
 ### 部署
 
-部署开始前，把  `_config.yml` 的 `url` 改为 `https://<username>.github.io`(或者您的私有域名，如：`https://yourdomain.com`)。另外，如果您想使用 [Project 类型网站](https://help.github.com/en/github/working-with-github-pages/about-github-pages#types-of-github-pages-sites)，修改配置文件的 `baseurl` 为项目名称，以斜杠开头，如：`/project`。
+部署开始前，把  `_config.yml` 的 `url` 改为 `https://<username>.github.io`（或者您的私有域名，如：`https://yourdomain.com`）。另外，如果您想使用 [Project 类型网站](https://help.github.com/en/github/working-with-github-pages/about-github-pages#types-of-github-pages-sites)，修改配置文件的 `baseurl` 为项目名称，以斜杠开头，如：`/project`。
 
 现在您可以选择下列其中一个方式去站点部署。
 
-#### 部署到 GitHub Pages
+#### 使用 GitHub Actions 部署
 
-由于安全原因，GitHub Pages 的构建强制加了 `safe`参数，这导致了我们不能使用插件去创建所需的附加页面。因此，我们可以使用 GitHub Actions 去构建站点，把站点文件存储在一个新分支上，再指定该分支作为 Pages 服务的源。
+由于安全原因，默认的 GitHub Pages 的构建强制加了 `safe`参数，这导致了我们不能使用插件去创建所需的附加页面。因此，我们可以使用 GitHub Actions 去构建站点，把站点文件存储在一个新分支上，再指定该分支作为 Pages 服务的源。
 
 快速检查 GitHub Actions 构建需要的文件:
 
-- 确保您的 Jekyll 站点存在文件 `.github/workflows/pages-deploy.yml`。没有的话，新建并填入[示例工作流][workflow]的内容, 注意参数 `on.push.branches` 的值必须和您的仓库默认分支名相同。
-- 检查您的 Jekyll 站点是否有文件 `tools/test.sh` 和 `tools/deploy.sh`. 没有的话, 从本仓库拷贝到您的 Jekyll 项目.
+- 确保您的 Jekyll 站点存在文件 `.github/workflows/pages-deploy.yml`。没有的话，新建并填入「[示例 Workflow][workflow]」的内容，注意参数 `on.push.branches` 的值必须和您的仓库默认分支名相同。
 
-在 GitHub 把您的仓库命名为 `<GH-USERNAME>.github.io`，然后开始发布：
+- 检查您的 Jekyll 站点是否有文件 `tools/deploy.sh`。没有的话， 从本仓库拷贝到您的 Jekyll 项目。
+
+- 再者，如果您已经把文件 `Gemfile.lock` 提交到了仓库里面，并且您运行本项目的操作系统不是 Linux，需要添加新的平台信息：
+
+  ```console
+  $ bundle lock --add-platform x86_64-linux
+  ```
+
+完成上述条目后，到 GitHub 把您的仓库命名为 `<GH-USERNAME>.github.io`，然后开始发布：
 
 1. 推送任意一个 commit 到 `origin/master` 以触发 GitHub Actions workflow。一旦 build 完毕并且成功，远端将会自动出现一个新分支 `gh-pages` 用来存储构建的站点文件。
 
-2. 回到 GitHub 上的仓库， 通过 _Settings_ → _Options_ → _GitHub Pages_ 选择分支 `gh-pages` 作为[_发布源_](https://docs.github.com/en/github/working-with-github-pages/configuring-a-publishing-source-for-your-github-pages-site):
+2. 回到 GitHub 上的仓库，选择标签 _Settings_ → 点击左侧导航栏的 _Pages_ → _GitHub Pages_ 选择分支 `gh-pages` 的 `/(root)` 作为「[发布源][pages-src]」:
 
     ![gh-pages-sources](https://cdn.jsdelivr.net/gh/cotes2020/chirpy-images/posts/20190809/gh-pages-sources.png)
 
 3. 按照 GitHub 指示的地址去访问您的网站。
 
-#### 部署到其他 Pages 平台
+#### 手动构建部署
 
-在 GitHub 之外的平台，例如 GitLab，就没法享受 **GitHub Actions** 的便利了。因此我们需要在本地构建站点（或者在其他第三方 CI 平台），然后推送站点文件到服务器上。
+在 GitHub 之外的平台，就没法享受 **GitHub Actions** 的便利了。因此您需要在本地构建站点，然后推送站点文件到服务器上。
 
 在项目根目录，运行:
 
@@ -213,25 +195,45 @@ $ docker run -it --rm \
 
 生成的静态文件将会在 `_site`， 把内部的文件上传到服务器即可。
 
+### 升级
+
+这取决于您如何使用这个 theme：
+
+- 如果您是使用 theme gem（`Gemfile` 会有 `gem "jekyll-theme-chirpy"`），编辑 `Gemfile` 并更新 them gem 的版本号，譬如：
+    ```diff
+    - gem "jekyll-theme-chirpy", "~> 3.2", ">= 3.2.1"
+    + gem "jekyll-theme-chirpy", "~> 3.3", ">= 3.3.0"
+    ```
+
+    接着执行以下命令：
+
+    ```console
+    $ bundle update jekyll-theme-chirpy
+    ```
+
+    随着 theme 版本的升级，运行站点的必要文件（详见 [Chirpy Starter][starter]）以及配置选项会出现变化，请参阅「[升级指南](https://github.com/cotes2020/jekyll-theme-chirpy/wiki/Upgrade-Guide)」的改动细节去保持您仓库中的相关文件同步到最新版本。
+
+- 如果您是以 fork 的方式使用（您站点的 `Gemfile` 会有 `gemspec`），那么合并上游 [最新的 tag][latest-tag] 到您的 Repo 以完成升级。期间很有可能会产生冲突 (conflicts)，请务必耐心谨慎地解决它们。
+
 ## 文档
 
-若想要更多细节以及更佳的阅读体验，请参阅 [线上教程](https://chirpy.cotes.info/categories/tutorial/)。 与此同时，[Wiki](https://github.com/cotes2020/jekyll-theme-chirpy/wiki) 也有一份教程的拷贝。请注意，Demo 网站和 Wiki 上的文档都是基于最新的发行版本，而 `master` 分支的功能往往领先于现有文档。
+若想要更多细节以及更佳的阅读体验，请参阅「[线上教程](https://chirpy.cotes.info/categories/tutorial/)」。 与此同时，「[Wiki](https://github.com/cotes2020/jekyll-theme-chirpy/wiki)」也有一份教程的拷贝。请注意，Demo 网站和 Wiki 上的文档都是基于最新的发行版本，而 `master` 分支的功能往往领先于现有文档。
 
 ## 参与贡献
 
-三人行必有我师，欢迎提报告 bug, 帮助改进代码质量，或者提交新功能。具体操作规则请参考 [贡献指南](../.github/CONTRIBUTING.md)，谢谢 🙏。
+三人行必有我师，欢迎提报告 bug，帮助改进代码质量，或者提交新功能。具体操作规则请参考「[贡献指南](../.github/CONTRIBUTING.md)」，谢谢 🙏。
 
 ## 鸣谢
 
-这个主题的开发主要基于 [Jekyll](https://jekyllrb.com/) 生态、[Bootstrap](https://getbootstrap.com/)、[Font Awesome](https://fontawesome.com/) 和其他一些出色的工具 (相关文件中可以找到这些工具的版权信息)。头像和图标的设计来自于 [Clipart Max](https://www.clipartmax.com/middle/m2i8b1m2K9Z5m2K9_ant-clipart-childrens-ant-cute/)。
+此款主题的开发主要基于 [Jekyll](https://jekyllrb.com/) 生态、[Bootstrap](https://getbootstrap.com/)、[Font Awesome](https://fontawesome.com/) 和其他一些出色的工具 (相关文件中可以找到这些工具的版权信息)。头像和图标的设计来自于 [Clipart Max](https://www.clipartmax.com/middle/m2i8b1m2K9Z5m2K9_ant-clipart-childrens-ant-cute/)。
 
-:tada: 感谢所有参与代码贡献的小伙伴, 他们的 GayHub ID 在这个[列表](https://github.com/cotes2020/jekyll-theme-chirpy/graphs/contributors)。 另外, 提交过 issues(或者未被合并 PR) 的高富帅和白富美也不会被遗忘,他/她们帮助报告 bug、分享新点子或者启发了我写出更通俗易懂的文档。
+:tada: 感谢所有参与代码贡献的小伙伴，他们的 GayHub ID 在这个「[列表](https://github.com/cotes2020/jekyll-theme-chirpy/graphs/contributors)」。 另外，提交过 issues（或者未被合并 PR）的高富帅和白富美也不会被遗忘，他/她们帮助报告 bug、分享新点子或者启发了我写出更通俗易懂的文档。
 
 还有，感谢 [JetBrains][jb] 提供开源 License！
 
 ## 赞助
 
-如果您喜欢这个主题或者它对您有帮助，请考虑打赏作者，您的支持将会极大地鼓励作者，并帮助作者更好地维护项目！
+如果您喜欢此款主题或者它对您有帮助，请考虑打赏作者，您的支持将会极大地鼓励作者，并帮助作者更好地维护项目！
 
 [![Buy Me a Coffee](https://img.shields.io/badge/-请作者喝杯咖啡-ff813f?logo=buy-me-a-coffee&logoColor=white)](https://www.buymeacoffee.com/coteschung)
 [![Wechat Pay](https://img.shields.io/badge/-微信打赏作者-brightgreen?logo=wechat&logoColor=white)][cn-donation]
@@ -244,6 +246,9 @@ $ docker run -it --rm \
 [starter]: https://github.com/cotes2020/chirpy-starter
 [use-starter]: https://github.com/cotes2020/chirpy-starter/generate
 [workflow]: https://github.com/cotes2020/jekyll-theme-chirpy/blob/master/.github/workflows/pages-deploy.yml.hook
+[chirpy-4.1.0]: https://github.com/cotes2020/jekyll-theme-chirpy/releases/tag/v4.1.0
+[pages-src]: https://docs.github.com/en/github/working-with-github-pages/configuring-a-publishing-source-for-your-github-pages-site
+[latest-tag]: https://github.com/cotes2020/jekyll-theme-chirpy/tags
 
 <!-- ReadMe links -->