diff --git a/CHANGES.md b/CHANGES.md
index 0a6e63a..c3a096b 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,7 +1,7 @@
-# Master (unreleased)
+# v0.4.0.beta
 
 * Automatic assets registration for Hanami and Sprockets without Rails.
-* KaTeX v0.9.0-alpha2.
+* KaTeX v0.9.0-beta.
 
 # v0.3.0
 
diff --git a/README.md b/README.md
index 827d201..f5bdd00 100644
--- a/README.md
+++ b/README.md
@@ -8,7 +8,7 @@ It uses [ExecJS] under the hood.
 Add this line to your application's Gemfile:
 
 ```ruby
-gem 'katex', '~> 0.3.0'
+gem 'katex', '~> 0.4.0.beta'
 ```
 
 And then execute:
diff --git a/lib/katex/version.rb b/lib/katex/version.rb
index bc89d43..fb87a54 100644
--- a/lib/katex/version.rb
+++ b/lib/katex/version.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
 module Katex
-  VERSION = '0.3.0'
+  VERSION = '0.4.0.beta'
   KATEX_VERSION = 'v0.9.0-beta'
 end