diff --git a/Casks/earlybird.rb b/Casks/earlybird.rb
index 3830cd1a7..303ccecd3 100644
--- a/Casks/earlybird.rb
+++ b/Casks/earlybird.rb
@@ -1,5 +1,5 @@
 cask :v1 => 'earlybird' do
-  version '42.0a2'
+  version '43.0a2'
   sha256 :no_check  # required as upstream package is updated in-placea
 
   url "https://ftp.mozilla.org/pub/mozilla.org/thunderbird/nightly/latest-earlybird/thunderbird-#{version}.en-US.mac.dmg"