diff --git a/.rubocop.yml b/.rubocop.yml
index 480c652..3fd4974 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -5,10 +5,18 @@ AllCops:
     - 'turkish_cities.gemspec'
 Layout/LineLength:
   Max: 100
+Layout/SpaceAroundMethodCallOperator:
+  Enabled: true
+Lint/RaiseException:
+  Enabled: true
+Lint/StructNewOverride:
+  Enabled: true
 Metrics/BlockLength:
   ExcludedMethods: ['describe', 'context']
 Style/Documentation:
   Enabled: false
+Style/ExponentialNotation:
+  Enabled: true
 Style/HashEachMethods:
   Enabled: true
 Style/HashTransformKeys:
@@ -17,4 +25,3 @@ Style/HashTransformKeys:
 Style/HashTransformValues:
   Description: 'Prefer `transform_values` over `each_with_object` and `map`.'
   Enabled: true
-    
\ No newline at end of file
diff --git a/Gemfile.lock b/Gemfile.lock
index 0acac0c..5e824f4 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -22,7 +22,7 @@ GEM
     jaro_winkler (1.5.4)
     json (2.3.0)
     parallel (1.19.1)
-    parser (2.7.1.0)
+    parser (2.7.1.1)
       ast (~> 2.4.0)
     rainbow (3.0.0)
     rexml (3.2.4)
@@ -39,14 +39,14 @@ GEM
       diff-lcs (>= 1.2.0, < 2.0)
       rspec-support (~> 3.9.0)
     rspec-support (3.9.2)
-    rubocop (0.80.1)
+    rubocop (0.82.0)
       jaro_winkler (~> 1.5.1)
       parallel (~> 1.10)
       parser (>= 2.7.0.1)
       rainbow (>= 2.2.2, < 4.0)
       rexml
       ruby-progressbar (~> 1.7)
-      unicode-display_width (>= 1.4.0, < 1.7)
+      unicode-display_width (>= 1.4.0, < 2.0)
     ruby-progressbar (1.10.1)
     simplecov (0.16.1)
       docile (~> 1.1)
@@ -59,7 +59,7 @@ GEM
     thor (1.0.1)
     tins (1.24.1)
       sync
-    unicode-display_width (1.6.1)
+    unicode-display_width (1.7.0)
 
 PLATFORMS
   ruby
@@ -68,7 +68,7 @@ DEPENDENCIES
   bundler (~> 2.1.4)
   coveralls (~> 0.8.23)
   rspec (~> 3.9.0)
-  rubocop (~> 0.80.1)
+  rubocop (~> 0.82.0)
   turkish_cities!
 
 BUNDLED WITH
diff --git a/spec/turkish_cities_spec.rb b/spec/turkish_cities_spec.rb
index 0efdd46..54a008c 100644
--- a/spec/turkish_cities_spec.rb
+++ b/spec/turkish_cities_spec.rb
@@ -25,6 +25,8 @@
     expect(TurkishCities.find_name_by_phone_code(242)).to eq 'Antalya'
     expect(TurkishCities.find_name_by_phone_code(222)).to eq 'Eskişehir'
     expect(TurkishCities.find_name_by_phone_code(274)).to eq 'Kütahya'
+    expect(TurkishCities.find_name_by_phone_code(212)).to eq 'İstanbul'
+    expect(TurkishCities.find_name_by_phone_code(216)).to eq 'İstanbul'
     expect(TurkishCities.find_name_by_phone_code(370)).to eq 'Karabük'
     expect(TurkishCities.find_name_by_phone_code(360))
       .to eq "Couldn't find city name with phone code 360"
diff --git a/turkish_cities.gemspec b/turkish_cities.gemspec
index cce2e1d..0fd3526 100644
--- a/turkish_cities.gemspec
+++ b/turkish_cities.gemspec
@@ -24,7 +24,7 @@ Gem::Specification.new do |s|
   s.add_development_dependency 'bundler', '~> 2.1.4'
   s.add_development_dependency 'coveralls', '~> 0.8.23'
   s.add_development_dependency 'rspec', '~> 3.9.0'
-  s.add_development_dependency 'rubocop', '~> 0.80.1'
+  s.add_development_dependency 'rubocop', '~> 0.82.0'
 
   if s.respond_to?(:metadata)
     s.metadata['changelog_uri'] = 'https://github.com/sarslanoglu/turkish_cities/blob/master/CHANGELOG.md'