diff --git a/CHANGELOG.md b/CHANGELOG.md
index 19a7808..f4442c2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,4 +1,4 @@
-0.3.8
+0.4.0
 -----
 
 - Fix to work with workers with one optional argument [nata79]
diff --git a/lib/sidetiq/version.rb b/lib/sidetiq/version.rb
index 3e5c4a3..be64a55 100644
--- a/lib/sidetiq/version.rb
+++ b/lib/sidetiq/version.rb
@@ -10,8 +10,11 @@ module Sidetiq
     # Public: Sidetiq patch level.
     PATCH = 7
 
+    # Public: Sidetiq version suffix.
+    SUFFIX = 'rc1'
+
     # Public: String representation of the current Sidetiq version.
-    STRING = [MAJOR, MINOR, PATCH].compact.join('.')
+    STRING = [MAJOR, MINOR, PATCH, SUFFIX].compact.join('.')
   end
 end
 
diff --git a/test/test_version.rb b/test/test_version.rb
index 7d8d33b..e78dc58 100644
--- a/test/test_version.rb
+++ b/test/test_version.rb
@@ -15,7 +15,8 @@ class TestVersion < Sidetiq::TestCase
 
   def test_string
     assert_equal Sidetiq::VERSION::STRING, [Sidetiq::VERSION::MAJOR,
-      Sidetiq::VERSION::MINOR, Sidetiq::VERSION::PATCH].compact.join('.')
+                                            Sidetiq::VERSION::MINOR, Sidetiq::VERSION::PATCH,
+                                            Sidetiq::VERSION::SUFFIX].compact.join('.')
   end
 end