diff --git a/.github/workflows/pr-build.yml b/.github/workflows/pr-build.yml
index 20bbc0d..4eabd25 100644
--- a/.github/workflows/pr-build.yml
+++ b/.github/workflows/pr-build.yml
@@ -8,12 +8,8 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
 
-    - name: Download bootstrap file
-      run: wget https://raw.githubusercontent.com/progit/progit2-pub/master/bootstrap.sh
-    - name: Run bootstrap
-      run: sh bootstrap.sh
     - name: Set up Ruby
       uses: ruby/setup-ruby@v1
       with:
@@ -21,4 +17,4 @@ jobs:
         bundler-cache: true # runs 'bundle install' and caches installed gems automatically
 
     - name: Build book
-      run: bundle exec rake book:build_action
+      run: bundle exec rake book:build
diff --git a/.github/workflows/release-on-merge.yml b/.github/workflows/release-on-merge.yml
index 3c877b8..109383f 100644
--- a/.github/workflows/release-on-merge.yml
+++ b/.github/workflows/release-on-merge.yml
@@ -8,21 +8,17 @@ jobs:
   release:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
       with:
         fetch-depth: 0
-    - name: get bootstrap file
-      run: wget https://raw.githubusercontent.com/progit/progit2-pub/master/bootstrap.sh
-    - name: run bootstrap
-      run: sh bootstrap.sh
     - name: Compute tag name
       id: compute-tag
       run: |
         echo Computing next tag number
         LASTPATCH=$(git describe --tags | cut -d- -f1 | cut -d. -f3)
         PATCH=$(($LASTPATCH+1))
-        echo "::set-output name=tagname::2.1.${PATCH}"
-        echo "::set-output name=branch::${GITHUB_REF#refs/heads/}"
+        echo "tagname=2.1.${PATCH}" >> $GITHUB_OUTPUT
+        echo "branch=${GITHUB_REF#refs/heads/}" >> $GITHUB_OUTPUT
 
     - name: Set up Ruby
       uses: ruby/setup-ruby@v1
@@ -31,7 +27,7 @@ jobs:
         bundler-cache: true # runs 'bundle install' and caches installed gems automatically
 
     - name: Build release assets
-      run: bundle exec rake book:build_action
+      run: bundle exec rake book:build
 
     - name: Create release
       uses: ncipollo/release-action@v1
@@ -39,4 +35,4 @@ jobs:
         token: ${{ secrets.GITHUB_TOKEN }}
         tag: ${{ steps.compute-tag.outputs.tagname }}
         commit: ${{ steps.compute-tag.outputs.branch }}
-        artifacts: './progit.epub,./progit.mobi,./progit.pdf,./progit.html'
+        artifacts: './progit.epub,./progit.fb2.zip,./progit.mobi,./progit.pdf,./progit.html'
diff --git a/.gitignore b/.gitignore
index 424a30e..6edb8af 100644
--- a/.gitignore
+++ b/.gitignore
@@ -7,6 +7,8 @@ progit.html
 progit.pdf
 progit.pdfmarks
 progit.epub
+progit.fb2.zip
 progit-kf8.epub
 progit.mobi
-contributors.txt
\ No newline at end of file
+contributors.txt
+progit.mobi8
diff --git a/Gemfile b/Gemfile
index ee74b4a..2211a4f 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,18 +1,24 @@
 source 'https://rubygems.org'
 
-gem 'rake', '13.0.3'
-gem 'asciidoctor', '2.0.15'
+gem 'ffi', '1.16.3'
+gem 'rake'
+gem 'asciidoctor', '2.0.12'
 
-gem 'json', '2.5.1'
-gem 'awesome_print', '1.9.2'
+gem 'json'
+gem 'awesome_print'
 
-gem 'asciidoctor-epub3', '1.5.0.alpha.19'
-gem 'asciidoctor-pdf', '1.5.4'
+gem 'ttfunk', '1.5.1'
+gem 'asciidoctor-fb2'
+gem 'asciidoctor-epub3', '1.5.0.alpha.11'
+gem 'asciidoctor-pdf', '1.5.0.alpha.16'
 gem 'asciidoctor-pdf-cjk', '~> 0.1.3'
-gem 'asciidoctor-pdf-cjk-kai_gen_gothic', '~> 0.1.1'
+gem 'asciidoctor-pdf-cjk-kai_gen_gothic', github: 'Sherry520/asciidoctor-pdf-cjk-kai_gen_gothic'
 
-gem 'coderay', '1.1.3'
-gem 'pygments.rb', '2.2.0'
-gem 'thread_safe', '0.3.6'
-gem 'epubcheck-ruby', '4.2.5.0'
-gem 'html-proofer', '3.19.0'
+gem 'coderay'
+gem 'pygments.rb'
+gem 'thread_safe'
+gem 'epubcheck-ruby'
+gem 'html-proofer'
+
+gem 'kindlegen', '3.1.1'
+gem 'nokogiri', '~> 1.13', '>= 1.13.10'
diff --git a/Rakefile b/Rakefile
index ae49df0..cb01f18 100644
--- a/Rakefile
+++ b/Rakefile
@@ -1,19 +1,51 @@
-namespace :book do
-  def exec_or_raise(command)
-    puts `#{command}`
-    if (! $?.success?)
-      raise "'#{command}' failed"
-    end
+def exec_or_raise(command)
+  puts `#{command}`
+  if (! $?.success?)
+    raise "'#{command}' failed"
   end
+end
+
+namespace :book do
+
+  # Download asciidoctor-pdf-cjk-kai_gen_gothic
+  exec_or_raise("asciidoctor-pdf-cjk-kai_gen_gothic-install")
 
   # Variables referenced for build
-  version_string = ENV['TRAVIS_TAG'] || `git describe --tags`.chomp
+  version_string = `git describe --tags --abbrev=0`.chomp
   if version_string.empty?
     version_string = '0'
+  else
+    versions = version_string.split('.')
+    version_string = versions[0] + '.' + versions[1] + '.' + versions[2].to_i.next.to_s
   end
   date_string = Time.now.strftime('%Y-%m-%d')
-  params = "--attribute revnumber='#{version_string}' --attribute revdate='#{date_string}'"
   header_hash = `git rev-parse --short HEAD`.strip
+  
+  # Check language
+  repo = File.basename(`git rev-parse --show-toplevel`.chomp)
+  lang_match = repo.match(/progit2-([a-z-]*)/)
+  if lang_match
+    lang = lang_match[1]
+  else
+    lang = "en"
+  end
+
+  begin
+    if lang == "zh"
+      params = "-r asciidoctor-pdf-cjk -r asciidoctor-pdf-cjk-kai_gen_gothic -a pdf-style=KaiGenGothicCN --attribute revnumber='#{version_string}' --attribute revdate='#{date_string}' --attribute lang='#{lang}'"
+    elsif lang == "zh-tw"
+      params = "-r asciidoctor-pdf-cjk -r asciidoctor-pdf-cjk-kai_gen_gothic -a pdf-style=KaiGenGothicTW --attribute revnumber='#{version_string}' --attribute revdate='#{date_string}' --attribute lang='#{lang}'"
+    elsif lang == "ja"
+      params = "-r asciidoctor-pdf-cjk -r asciidoctor-pdf-cjk-kai_gen_gothic -a pdf-style=KaiGenGothicJP --attribute revnumber='#{version_string}' --attribute revdate='#{date_string}' --attribute lang='#{lang}'"
+    elsif lang == "ko"
+      params = "-r asciidoctor-pdf-cjk -r asciidoctor-pdf-cjk-kai_gen_gothic -a pdf-style=KaiGenGothicKR --attribute revnumber='#{version_string}' --attribute revdate='#{date_string}' --attribute lang='#{lang}'"
+    else
+      params = "--attribute revnumber='#{version_string}' --attribute revdate='#{date_string}'"
+    end
+  rescue => e
+    puts e.message
+    puts 'Error when checking repo language(ignored)'
+  end
 
   # Check contributors list
   # This checks commit hash stored in the header of list against current HEAD
@@ -28,7 +60,7 @@ namespace :book do
         puts "Hash on header of contributors list (#{header_hash}) matches the current HEAD (#{current_head_hash})"
       else
         puts "Hash on header of contributors list (#{header_hash}) does not match the current HEAD (#{current_head_hash}), refreshing"
-        `rm book/contributors.txt`
+        sh "rm book/contributors.txt"
         # Reenable and invoke task again
         Rake::Task['book/contributors.txt'].reenable
         Rake::Task['book/contributors.txt'].invoke
@@ -37,7 +69,7 @@ namespace :book do
   end
 
   desc 'build basic book formats'
-  task :build => [:build_html, :build_epub, :build_pdf] do
+  task :build => [:build_html, :build_epub, :build_fb2, :build_mobi, :build_pdf] do
     begin
         # Run check
         Rake::Task['book:check'].invoke
@@ -50,7 +82,7 @@ namespace :book do
   end
 
   desc 'build basic book formats (for ci)'
-  task :ci => [:build_html, :build_epub, :build_pdf] do
+  task :ci => [:build_html, :build_epub, :build_fb2, :build_mobi, :build_pdf] do
       # Run check, but don't ignore any errors
       Rake::Task['book:check'].invoke
   end
@@ -58,8 +90,8 @@ namespace :book do
   desc 'generate contributors list'
   file 'book/contributors.txt' do
       puts 'Generating contributors list'
-      `echo "Contributors as of #{header_hash}:\n" > book/contributors.txt`
-      `git shortlog -s | grep -v -E "(Straub|Chacon|dependabot)" | cut -f 2- | column -c 120 >> book/contributors.txt`
+      sh "echo 'Contributors as of #{header_hash}:\n' > book/contributors.txt"
+      sh "git shortlog -s HEAD | grep -v -E '(Straub|Chacon|dependabot)' | cut -f 2- | sort | column -c 120 >> book/contributors.txt"
   end
 
   desc 'build HTML format'
@@ -67,7 +99,7 @@ namespace :book do
       check_contrib()
 
       puts 'Converting to HTML...'
-      `bundle exec asciidoctor #{params} -a data-uri progit.asc`
+      sh "bundle exec asciidoctor #{params} -a data-uri progit.asc"
       puts ' -- HTML output at progit.html'
 
   end
@@ -77,25 +109,28 @@ namespace :book do
       check_contrib()
 
       puts 'Converting to EPub...'
-      `bundle exec asciidoctor-epub3 #{params} progit.asc`
+      sh "bundle exec asciidoctor-epub3 #{params} progit.asc"
       puts ' -- Epub output at progit.epub'
 
   end
 
+  desc 'build FB2 format'
+  task :build_fb2 => 'book/contributors.txt' do
+      check_contrib()
+
+      puts 'Converting to FB2...'
+      sh "bundle exec asciidoctor-fb2 #{params} progit.asc"
+      puts ' -- FB2 output at progit.fb2.zip'
+
+  end
+
   desc 'build Mobi format'
   task :build_mobi => 'book/contributors.txt' do
-      # Commented out the .mobi file creation because the kindlegen dependency is not available.
-      # For more information on this see: #1496.
-      # This is a (hopefully) temporary fix until upstream asciidoctor-epub3 is fixed and we can offer .mobi files again.
-
-      # puts "Converting to Mobi (kf8)..."
-      # `bundle exec asciidoctor-epub3 #{params} -a ebook-format=kf8 progit.asc`
-      # puts " -- Mobi output at progit.mobi"
-
-      # FIXME: If asciidoctor-epub3 supports Mobi again, uncomment these lines below
-      puts "Converting to Mobi isn't supported yet."
-      puts "For more information see issue #1496 at https://github.com/progit/progit2/issues/1496."
-      exit(127)
+      check_contrib()
+
+      puts "Converting to Mobi (kf8)..."
+      sh "bundle exec asciidoctor-epub3 #{params} -a ebook-format=kf8 progit.asc"
+      puts " -- Mobi output at progit.mobi"
   end
 
   desc 'build PDF format'
@@ -103,7 +138,7 @@ namespace :book do
       check_contrib()
 
       puts 'Converting to PDF... (this one takes a while)'
-      `bundle exec asciidoctor-pdf #{params} -a scripts=cjk -a pdf-theme=./korean-theme.yml -a pdf-fontsdir=$(ruby -r asciidoctor-pdf-cjk-kai_gen_gothic -e "print File.expand_path '../fonts', (Gem.datadir 'asciidoctor-pdf-cjk-kai_gen_gothic')") progit.asc 2>/dev/null`
+      sh "bundle exec asciidoctor-pdf #{params} progit.asc 2>/dev/null"
       puts ' -- PDF output at progit.pdf'
   end
 
@@ -111,8 +146,8 @@ namespace :book do
   task :check => [:build_html, :build_epub] do
       puts 'Checking generated books'
 
-      exec_or_raise('htmlproofer --check-html progit.html')
-      exec_or_raise('epubcheck progit.epub')
+      sh "htmlproofer progit.html"
+      sh "epubcheck progit.epub"
   end
 
   desc 'Clean all generated files'
@@ -120,7 +155,7 @@ namespace :book do
     begin
         puts 'Removing generated files'
 
-        FileList['book/contributors.txt', 'progit.html', 'progit.epub', 'progit.pdf'].each do |file|
+        FileList['book/contributors.txt', 'progit.html', 'progit-kf8.epub', 'progit.epub', 'progit.fb2.zip', 'progit.mobi', 'progit.pdf'].each do |file|
             rm file
 
             # Rescue if file not found