diff --git a/src/api/.rubocop.yml b/src/api/.rubocop.yml
index 25be35bd47e..f7a08bc0534 100644
--- a/src/api/.rubocop.yml
+++ b/src/api/.rubocop.yml
@@ -32,6 +32,10 @@ Style/AndOr:
 Style/AsciiComments:
   Enabled: true
 
+# Checks for methods invoked via the :: operator
+Style/ColonMethodCall:
+  Enabled: true
+
 # Use ` or %x around command literals.
 Style/CommandLiteral:
   EnforcedStyle: percent_x
diff --git a/src/api/.rubocop_todo.yml b/src/api/.rubocop_todo.yml
index ecc21df792f..d1ff6dbce05 100644
--- a/src/api/.rubocop_todo.yml
+++ b/src/api/.rubocop_todo.yml
@@ -338,19 +338,6 @@ Style/ClosingParenthesisIndentation:
   Exclude:
     - 'test/unit/project_test.rb'
 
-# Offense count: 14
-# Cop supports --auto-correct.
-Style/ColonMethodCall:
-  Exclude:
-    - 'app/controllers/configurations_controller.rb'
-    - 'app/controllers/webui/package_controller.rb'
-    - 'app/helpers/webui/project_helper.rb'
-    - 'app/mixins/build_log_support.rb'
-    - 'app/models/issue_tracker.rb'
-    - 'config/application.rb'
-    - 'config/initializers/activexml.rb'
-    - 'config/unicorn/development.rb'
-
 # Offense count: 18
 # Cop supports --auto-correct.
 # Configuration parameters: Keywords.
diff --git a/src/api/app/controllers/configurations_controller.rb b/src/api/app/controllers/configurations_controller.rb
index 008a0c30e6f..495da864007 100644
--- a/src/api/app/controllers/configurations_controller.rb
+++ b/src/api/app/controllers/configurations_controller.rb
@@ -49,8 +49,8 @@ def update
 
       # is it defined in options.yml
       if value && !value.blank?
-        v = ::Configuration::map_value( key, value )
-        ov = ::Configuration::map_value( key, ::Configuration::OPTIONS_YML[key] )
+        v = ::Configuration.map_value( key, value )
+        ov = ::Configuration.map_value( key, ::Configuration::OPTIONS_YML[key] )
         if ov != v && ov.present?
           render_error status: 403, errorcode: 'no_permission_to_change',
                        message: "The api has a different value for #{key} configured in options.yml file. Remove it there first."
diff --git a/src/api/app/controllers/webui/package_controller.rb b/src/api/app/controllers/webui/package_controller.rb
index d4d5f963150..11d8367cf08 100644
--- a/src/api/app/controllers/webui/package_controller.rb
+++ b/src/api/app/controllers/webui/package_controller.rb
@@ -849,7 +849,7 @@ def update_build_log
         @finished = true
       else
         @log_chunk = chunk
-        @offset += ActiveXML::backend.last_body_length
+        @offset += ActiveXML.backend.last_body_length
       end
 
     rescue Timeout::Error, IOError
@@ -973,7 +973,7 @@ def rpmlint_result
 
   def get_rpmlint_log(project, package, repository, architecture)
     path = "/build/#{pesc project}/#{pesc repository}/#{pesc architecture}/#{pesc package}/rpmlint.log"
-    ActiveXML::backend.direct_http(URI(path), timeout: 500)
+    ActiveXML.backend.direct_http(URI(path), timeout: 500)
   end
 
   def rpmlint_log
diff --git a/src/api/app/helpers/webui/project_helper.rb b/src/api/app/helpers/webui/project_helper.rb
index c367006150a..9731637907b 100644
--- a/src/api/app/helpers/webui/project_helper.rb
+++ b/src/api/app/helpers/webui/project_helper.rb
@@ -7,7 +7,7 @@ def show_status_comment(comment, package, firstfail, comments_to_clear)
     status_comment_html = ''.html_safe
     if comment
       # TODO: Port _to_remote helpers to jQuery
-      status_comment_html = ERB::Util::h(comment)
+      status_comment_html = ERB::Util.h(comment)
       if !firstfail
         if User.current.can_modify_project?(@project.api_obj)
           status_comment_html += ' '.html_safe + link_to(image_tag('comment_delete.png', size: '16x16', alt: 'Clear'),
diff --git a/src/api/app/mixins/build_log_support.rb b/src/api/app/mixins/build_log_support.rb
index 0f97ea6885b..45ba63ced84 100644
--- a/src/api/app/mixins/build_log_support.rb
+++ b/src/api/app/mixins/build_log_support.rb
@@ -4,7 +4,7 @@ module BuildLogSupport
   def raw_log_chunk( project, package, repo, arch, start, theend )
     logger.debug "get log chunk #{start}-#{theend}"
     path = "/build/#{pesc project}/#{pesc repo}/#{pesc arch}/#{pesc package}/_log?nostream=1&start=#{start}&end=#{theend}"
-    ActiveXML::backend.direct_http URI("#{path}"), timeout: 500
+    ActiveXML.backend.direct_http URI("#{path}"), timeout: 500
   end
 
   def get_log_chunk( project, package, repo, arch, start, theend )
@@ -30,7 +30,7 @@ def get_log_chunk( project, package, repo, arch, start, theend )
   def get_size_of_log( project, package, repo, arch)
     logger.debug 'get log entry'
     path = "/build/#{pesc project}/#{pesc repo}/#{pesc arch}/#{pesc package}/_log?view=entry"
-    data = ActiveXML::backend.direct_http URI("#{path}"), timeout: 500
+    data = ActiveXML.backend.direct_http URI("#{path}"), timeout: 500
     return 0 unless data
     doc = Xmlhash.parse(data)
     doc.elements('entry') do |e|
@@ -41,13 +41,13 @@ def get_size_of_log( project, package, repo, arch)
 
   def get_job_status( project, package, repo, arch)
     path = "/build/#{pesc project}/#{pesc repo}/#{pesc arch}/#{pesc package}/_jobstatus"
-    ActiveXML::backend.direct_http URI("#{path}"), timeout: 500
+    ActiveXML.backend.direct_http URI("#{path}"), timeout: 500
   end
 
   def get_status(project, package, repo, arch)
     path = "/build/#{pesc project}/_result?view=status&package=#{pesc package}&arch=#{pesc arch}&repository=#{pesc repo}"
     code = ""
-    data = ActiveXML::backend.direct_http URI("#{path}"), timeout: 500
+    data = ActiveXML.backend.direct_http URI("#{path}"), timeout: 500
     return code unless data
     doc = Xmlhash.parse(data)
     if doc['result'] && doc['result']['status'] && doc['result']['status']['code']
diff --git a/src/api/app/models/issue_tracker.rb b/src/api/app/models/issue_tracker.rb
index 2961817f730..6bbecd14640 100644
--- a/src/api/app/models/issue_tracker.rb
+++ b/src/api/app/models/issue_tracker.rb
@@ -50,7 +50,7 @@ def valid_issue_name?(name)
   def show_url_for(issue, html = nil)
     return unless issue
     url = show_url.gsub('@@@', issue)
-    return "<a href=\"#{url}\">#{CGI::escapeHTML(show_label_for(issue))}</a>" if html
+    return "<a href=\"#{url}\">#{CGI.escapeHTML(show_label_for(issue))}</a>" if html
     url
   end
 
diff --git a/src/api/config/application.rb b/src/api/config/application.rb
index a77d48d2118..ac3d3f2eb7a 100644
--- a/src/api/config/application.rb
+++ b/src/api/config/application.rb
@@ -5,7 +5,7 @@
 # Assets should be precompiled for production (so we don't need the gems loaded then)
 Bundler.require(*Rails.groups(assets: %w(development test)))
 require_relative '../lib/engines/base.rb'
-OBSEngine::load_engines
+OBSEngine.load_engines
 
 module OBSApi
   class Application < Rails::Application
diff --git a/src/api/config/initializers/activexml.rb b/src/api/config/initializers/activexml.rb
index ff858f1f780..95f77714357 100644
--- a/src/api/config/initializers/activexml.rb
+++ b/src/api/config/initializers/activexml.rb
@@ -3,7 +3,7 @@
 CONFIG['source_protocol'] ||= 'http'
 CONFIG['api_relative_url_root'] ||= ''
 
-map = ActiveXML::setup_transport_backend(CONFIG['source_protocol'], CONFIG['source_host'], CONFIG['source_port'])
+map = ActiveXML.setup_transport_backend(CONFIG['source_protocol'], CONFIG['source_host'], CONFIG['source_port'])
 
 map.connect :directory, 'rest:///source/:project/:package?:expand&:rev&:meta&:linkrev&:emptylink&:view&:extension&:lastworking&:withlinked&:deleted'
 map.connect :jobhistory, 'rest:///build/:project/:repository/:arch/_jobhistory?:package&:limit&:code'
@@ -33,7 +33,7 @@
   end
 end
 
-map = ActiveXML::setup_transport_api(CONFIG['frontend_protocol'], CONFIG['frontend_host'], CONFIG['frontend_port'], CONFIG['api_relative_url_root'])
+map = ActiveXML.setup_transport_api(CONFIG['frontend_protocol'], CONFIG['frontend_host'], CONFIG['frontend_port'], CONFIG['api_relative_url_root'])
 
 map.connect :webuiproject, 'rest:///source/:name/_meta?:view',
             delete: 'rest:///source/:name?:force',
diff --git a/src/api/config/unicorn/development.rb b/src/api/config/unicorn/development.rb
index 12c2acb7934..a41cde0c5ac 100644
--- a/src/api/config/unicorn/development.rb
+++ b/src/api/config/unicorn/development.rb
@@ -4,6 +4,6 @@
 after_fork do |server, _|
   listener = server.listener_opts.first[0]
   port = Integer(listener.split(':')[1])
-  ActiveXML::api.port = port
+  ActiveXML.api.port = port
   CONFIG['frontend_port'] = port
 end