diff --git a/Casks/firefoxdeveloperedition.rb b/Casks/firefoxdeveloperedition.rb
index 7f4b83002..87d0ab67e 100644
--- a/Casks/firefoxdeveloperedition.rb
+++ b/Casks/firefoxdeveloperedition.rb
@@ -1,40 +1,50 @@
 cask 'firefoxdeveloperedition' do
-  version :latest
-  sha256 :no_check
+  version '56.0b3'
 
   language 'cs' do
+    sha256 'f885f90aa9ce4d436706c37ba5c57ec1c6db6e3599392dcd9fb078095b653bb2'
     'cs'
   end
 
   language 'de' do
+    sha256 '94c6ddb05399f3ccd1cbba8d68672ceb465db43ef4f5242910d3d45741d513f1'
     'de'
   end
 
   language 'en', default: true do
+    sha256 'ce73bc16f26495ced481fdfdbdff8eb9a092a13e9ea629dc6ce279dac1da25fd'
     'en-US'
   end
 
   language 'ja' do
+    sha256 '76f07c6435f2e5c7261bf4cb55d68900d076e3403535de6214f409bce01dcf6c'
     'ja-JP-mac'
   end
 
   language 'ru' do
+    sha256 '0eca1a90a3cbf753847a5c861786ab47268855adf5bfff676771c31f6f0eb198'
     'ru'
   end
 
   language 'uk' do
+    sha256 '770fc01851fa954062c5b05cd013ef5a00f75379d4f56225e270fcea7ddeec00'
     'uk'
   end
 
   language 'zh-TW' do
+    sha256 '681714c5128a07cfd3ba51316444a74411c059a2c6743cd8d5406876ada421ba'
     'zh-TW'
   end
 
   language 'zh' do
+    sha256 '145899a88936f8e1b0313b9aabd49d3b3886ba1257518a376f305da1d26993c0'
     'zh-CN'
   end
 
-  url "https://download.mozilla.org/?product=firefox-devedition-latest-ssl&os=osx&lang=#{language}"
+  # download-installer.cdn.mozilla.net/pub/devedition/releases was verified as official when first introduced to the cask
+  url "https://download-installer.cdn.mozilla.net/pub/devedition/releases/#{version}/mac/#{language}/Firefox%20#{version}.dmg"
+  appcast 'https://download-installer.cdn.mozilla.net/pub/devedition/releases/',
+          checkpoint: '732dddeb1476b75cb37da2b892aba3195c6d26bd61da831fe5a6446e11091f64'
   name 'Mozilla Firefox Developer Edition'
   homepage 'https://www.mozilla.org/firefox/developer/'