diff --git a/.rubocop.yml b/.rubocop.yml
index 3df1d8f..7fc88a4 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -117,3 +117,7 @@ Naming/FileName:
 Metrics/ModuleLength:
   Exclude:
     - 'test/**/*.rb'
+
+Performance/StringIdentifierArgument:
+  Exclude:
+    - 'test/**/*.rb'
diff --git a/Gemfile b/Gemfile
index 19f8772..fe3c1bd 100644
--- a/Gemfile
+++ b/Gemfile
@@ -12,7 +12,7 @@ gem 'minitest-proveit'
 gem 'prism'
 gem 'rake'
 gem 'rubocop', github: 'rubocop/rubocop'
-gem 'rubocop-performance', '~> 1.18.0'
+gem 'rubocop-performance', '~> 1.21.0'
 gem 'test-queue'
 gem 'yard', '~> 0.9'