diff --git a/Casks/firefox-beta.rb b/Casks/firefox-beta.rb
index 097b7d8e7..def995d95 100644
--- a/Casks/firefox-beta.rb
+++ b/Casks/firefox-beta.rb
@@ -1,6 +1,11 @@
 cask 'firefox-beta' do
   version '54.0b6'
 
+  language 'cs' do
+    sha256 '5bcd5ece0ac1923693a49771bfa8fa8ed7d32a41756b45338ab5e9a067014b3a'
+    'cs'
+  end
+
   language 'de' do
     sha256 '5777e9049438185f3a8dbb8fd7db3c79275d4b40dc090e483e43368d2ff1c177'
     'de'
@@ -72,7 +77,7 @@ cask 'firefox-beta' do
 
   url "https://download.mozilla.org/?product=firefox-#{version}-SSL&os=osx&lang=#{language}"
   name 'Mozilla Firefox'
-  homepage 'https://www.mozilla.org/firefox/channel/#beta'
+  homepage 'https://www.mozilla.org/firefox/channel/desktop/#beta'
 
   auto_updates true
 
diff --git a/Casks/firefox-esr.rb b/Casks/firefox-esr.rb
index cbd760d06..f0896204b 100644
--- a/Casks/firefox-esr.rb
+++ b/Casks/firefox-esr.rb
@@ -1,6 +1,11 @@
 cask 'firefox-esr' do
   version '52.1.0'
 
+  language 'cs' do
+    sha256 'baedabffbfdcef9d3cf08d1971a7b1c83293345f74130d64af32202de9bf6e97'
+    'cs'
+  end
+
   language 'de' do
     sha256 'd59a72100c1bd6339f3bbc40fe211f0a9a3fc16e9b1b51c067885f7c3c247e1c'
     'de'
diff --git a/Casks/firefoxnightly.rb b/Casks/firefoxnightly.rb
index 21ccdb68c..12ecd4318 100644
--- a/Casks/firefoxnightly.rb
+++ b/Casks/firefoxnightly.rb
@@ -2,6 +2,10 @@ cask 'firefoxnightly' do
   version '55.0a1'
   sha256 :no_check # required as upstream package is updated in-place
 
+  language 'cs' do
+    'cs'
+  end
+
   language 'en', default: true do
     'en-US'
   end
@@ -20,7 +24,7 @@ cask 'firefoxnightly' do
 
   url "https://ftp.mozilla.org/pub/firefox/nightly/latest-mozilla-central#{language == 'en-US' ? '' : '-l10n'}/firefox-#{version}.#{language}.mac.dmg"
   name 'Mozilla Firefox'
-  homepage 'https://www.mozilla.org/en-US/firefox/channel/desktop/'
+  homepage 'https://www.mozilla.org/firefox/channel/desktop/#nightly'
 
   app 'FirefoxNightly.app'