diff --git a/.rubocop_todo.yml b/.rubocop_todo.yml
index 6d6d02f5b..654fa16b6 100644
--- a/.rubocop_todo.yml
+++ b/.rubocop_todo.yml
@@ -1,6 +1,6 @@
 # This configuration was generated by
 # `rubocop --auto-gen-config --exclude-limit 20 --no-offense-counts --no-auto-gen-timestamp`
-# using RuboCop version 1.8.1.
+# using RuboCop version 1.9.1.
 # The point is for the user to remove these configuration records
 # one by one as the offenses are removed from the code base.
 # Note that changes in the inspected code, or installation of new
@@ -1284,6 +1284,17 @@ Style/IfUnlessModifierOfIfUnless:
   Exclude:
     - 'app/models/attachment.rb'
 
+# Cop supports --auto-correct.
+# Configuration parameters: AllowedMethods.
+# AllowedMethods: nonzero?
+Style/IfWithBooleanLiteralBranches:
+  Exclude:
+    - 'app/controllers/workflows_controller.rb'
+    - 'app/helpers/application_helper.rb'
+    - 'app/models/enumeration.rb'
+    - 'app/models/query.rb'
+    - 'lib/redmine/field_format.rb'
+
 # Cop supports --auto-correct.
 # Configuration parameters: InverseMethods, InverseBlocks.
 Style/InverseMethods:
diff --git a/Gemfile b/Gemfile
index a254636aa..8d0c19d68 100644
--- a/Gemfile
+++ b/Gemfile
@@ -92,7 +92,7 @@ group :test do
   gem 'capybara', '~> 3.31.0'
   gem "selenium-webdriver"
   # RuboCop
-  gem 'rubocop', '~> 1.8.1'
+  gem 'rubocop', '~> 1.9.1'
   gem 'rubocop-performance', '~> 1.9.0'
   gem 'rubocop-rails', '~> 2.9.0'
 end