diff --git a/.rubocop.yml b/.rubocop.yml
index 886aabb..287f769 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -9,30 +9,12 @@ AllCops:
   TargetRubyVersion: 2.3
   TargetRailsVersion: 5.2
 
-Metrics/AbcSize:
+Metrics:
   Enabled: false
 
-Metrics/BlockLength:
-  Enabled: false
-
-Metrics/ClassLength:
-  Enabled: false
-
-Metrics/CyclomaticComplexity:
-  Max: 20
-
 Layout/LineLength:
   Max: 140
 
-Metrics/MethodLength:
-  Max: 60
-
-Metrics/ModuleLength:
-  Enabled: false
-
-Metrics/PerceivedComplexity:
-  Max: 25
-
 Rails/ApplicationJob:
   Enabled: false
 
diff --git a/.travis.yml b/.travis.yml
index 89e34b9..971a6fc 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -34,6 +34,7 @@ before_install:
   - git clone $REDMINE_GIT_REPO $REDMINE_PATH
   - cd $REDMINE_PATH
   - if [[ "$REDMINE_VER" != "master" ]]; then git checkout -b $REDMINE_VER origin/$REDMINE_VER; fi
+  - if [[ "$REDMINE_VER" != "master" ]]; then cp $TRAVIS_BUILD_DIR/test/support/Gemfile.local $REDMINE_PATH; fi
   - ln -s $TRAVIS_BUILD_DIR $REDMINE_PATH/plugins/$PLUGIN_NAME
   - cp $TRAVIS_BUILD_DIR/test/support/additional_environment.rb $REDMINE_PATH/config/
   - cp $TRAVIS_BUILD_DIR/test/support/database-$DB-travis.yml $REDMINE_PATH/config/database.yml
@@ -43,4 +44,5 @@ before_script:
 
 script:
   - export SKIP_COVERAGE=1
+  - if [[ "$REDMINE_VER" != "master" ]] && [[ "$DB" == "postgresql" ]]; then rubocop plugins/$PLUGIN_NAME; fi
   - bundle exec rake redmine:plugins:test NAME=$PLUGIN_NAME RUBYOPT="-W0"
diff --git a/app/models/messenger.rb b/app/models/messenger.rb
index cdefda6..69d665d 100644
--- a/app/models/messenger.rb
+++ b/app/models/messenger.rb
@@ -158,9 +158,9 @@ class Messenger
       escape = true
 
       if detail.property == 'cf'
-        key = CustomField.find(detail.prop_key).name rescue nil
+        key = CustomField.find(detail.prop_key)&.name
         title = key
-        field_format = CustomField.find(detail.prop_key).field_format rescue nil
+        field_format = CustomField.find(detail.prop_key)&.field_format
       elsif detail.property == 'attachment'
         key = 'attachment'
         title = I18n.t :label_attachment
diff --git a/lib/redmine_messenger/hooks.rb b/lib/redmine_messenger/hooks.rb
index bc191eb..1b0a62d 100644
--- a/lib/redmine_messenger/hooks.rb
+++ b/lib/redmine_messenger/hooks.rb
@@ -11,7 +11,8 @@ module RedmineMessenger
       return unless channels.present? && url && issue.changes.any? && Messenger.setting_for_project(issue.project, :post_updates)
       return if issue.is_private? && !Messenger.setting_for_project(issue.project, :post_private_issues)
 
-      msg = "[#{Messenger.markup_format(issue.project)}] #{Messenger.markup_format(journal.user.to_s)} updated <#{Messenger.object_url issue}|#{Messenger.markup_format(issue)}>"
+      msg = "[#{Messenger.markup_format(issue.project)}]" \
+            " #{Messenger.markup_format(journal.user.to_s)} updated <#{Messenger.object_url issue}|#{Messenger.markup_format(issue)}>"
 
       repository = changeset.repository
 
@@ -43,7 +44,9 @@ module RedmineMessenger
       end
 
       attachment = {}
-      attachment[:text] = ll(Setting.default_language, :text_status_changed_by_changeset, "<#{revision_url}|#{Messenger.markup_format(changeset.comments)}>")
+      attachment[:text] = ll(Setting.default_language,
+                             :text_status_changed_by_changeset,
+                             "<#{revision_url}|#{Messenger.markup_format(changeset.comments)}>")
       attachment[:fields] = journal.details.map { |d| Messenger.detail_to_field d }
 
       Messenger.speak(msg, channels, url, attachment: attachment, project: repository.project)
diff --git a/test/support/Gemfile.local b/test/support/Gemfile.local
new file mode 100644
index 0000000..aad214b
--- /dev/null
+++ b/test/support/Gemfile.local
@@ -0,0 +1,3 @@
+gem 'rubocop', require: false
+gem 'rubocop-performance', require: false
+gem 'rubocop-rails', require: false