diff --git a/.rubocop.yml b/.rubocop.yml
index 70e2ca4..c39ca90 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -2,6 +2,7 @@ inherit_from: .rubocop_todo.yml
 
 AllCops:
   NewCops: enable
+  TargetRubyVersion: 3.0
 
 Metrics/BlockLength:
   CountAsOne: [array, hash, heredoc, method_call]
diff --git a/lib/grape_logging/loggers/filter_parameters.rb b/lib/grape_logging/loggers/filter_parameters.rb
index a169d18..c5f0870 100644
--- a/lib/grape_logging/loggers/filter_parameters.rb
+++ b/lib/grape_logging/loggers/filter_parameters.rb
@@ -31,7 +31,7 @@ def safe_parameters(request)
       def clean_parameters(parameters)
         original_encoding_map = build_encoding_map(parameters)
         params = transform_key_encoding(parameters, Hash.new { |h, _| [Encoding::ASCII_8BIT, h] })
-        cleaned_params = parameter_filter.filter(params).reject { |key, _value| @exceptions.include?(key) }
+        cleaned_params = parameter_filter.filter(params).except(*@exceptions)
         transform_key_encoding(cleaned_params, original_encoding_map)
       end
 
diff --git a/spec/lib/grape_logging/loggers/client_env_spec.rb b/spec/lib/grape_logging/loggers/client_env_spec.rb
index 3d490fa..c154aae 100644
--- a/spec/lib/grape_logging/loggers/client_env_spec.rb
+++ b/spec/lib/grape_logging/loggers/client_env_spec.rb
@@ -1,5 +1,4 @@
 require 'spec_helper'
-require 'ostruct'
 
 describe GrapeLogging::Loggers::ClientEnv do
   let(:ip) { '10.0.0.1' }
@@ -9,9 +8,9 @@
 
   context 'forwarded for' do
     let(:mock_request) do
-      OpenStruct.new(env: {
-                       'HTTP_X_FORWARDED_FOR' => forwarded_for
-                     })
+      instance_double(Rack::Request, env: {
+                        'HTTP_X_FORWARDED_FOR' => forwarded_for
+                      })
     end
 
     it 'sets the ip key' do
@@ -26,9 +25,9 @@
 
   context 'remote address' do
     let(:mock_request) do
-      OpenStruct.new(env: {
-                       'REMOTE_ADDR' => remote_addr
-                     })
+      instance_double(Rack::Request, env: {
+                        'REMOTE_ADDR' => remote_addr
+                      })
     end
 
     it 'sets the ip key' do
@@ -38,9 +37,9 @@
 
   context 'user agent' do
     let(:mock_request) do
-      OpenStruct.new(env: {
-                       'HTTP_USER_AGENT' => user_agent
-                     })
+      instance_double(Rack::Request, env: {
+                        'HTTP_USER_AGENT' => user_agent
+                      })
     end
 
     it 'sets the ua key' do
diff --git a/spec/lib/grape_logging/loggers/filter_parameters_spec.rb b/spec/lib/grape_logging/loggers/filter_parameters_spec.rb
index 5cc81a8..4864a9e 100644
--- a/spec/lib/grape_logging/loggers/filter_parameters_spec.rb
+++ b/spec/lib/grape_logging/loggers/filter_parameters_spec.rb
@@ -1,29 +1,27 @@
 require 'spec_helper'
-require 'ostruct'
 
 describe GrapeLogging::Loggers::FilterParameters do
   let(:filtered_parameters) { %w[one four] }
 
   let(:mock_request) do
-    OpenStruct.new(params: {
-                     'this_one' => 'this one',
-                     'that_one' => 'one',
-                     'two' => 'two',
-                     'three' => 'three',
-                     'four' => 'four',
-                     "\xff" => 'invalid utf8'
-                   })
+    instance_double(Rack::Request, params: {
+                      'this_one' => 'this one',
+                      'that_one' => 'one',
+                      'two' => 'two',
+                      'three' => 'three',
+                      'four' => 'four',
+                      "\xff" => 'invalid utf8'
+                    })
   end
 
   let(:mock_request_with_deep_nesting) do
     deep_clone = -> { Marshal.load Marshal.dump mock_request.params }
-    OpenStruct.new(
-      params: deep_clone.call.merge(
-        'five' => deep_clone.call.merge(
-          deep_clone.call.merge({ 'six' => { 'seven' => 'seven', 'eight' => 'eight', 'one' => 'another one' } })
-        )
-      )
-    )
+    instance_double(Rack::Request,
+                    params: deep_clone.call.merge(
+                      'five' => deep_clone.call.merge(
+                        deep_clone.call.merge({ 'six' => { 'seven' => 'seven', 'eight' => 'eight', 'one' => 'another one' } })
+                      )
+                    ))
   end
 
   let(:subject) do
@@ -79,7 +77,7 @@
   end
 
   context 'with symbol keys, which occur during automated testing' do
-    let(:mock_request) { OpenStruct.new(params: { sneaky_symbol: 'hey!' }) }
+    let(:mock_request) { instance_double(Rack::Request, params: { sneaky_symbol: 'hey!' }) }
 
     it 'converts keys to strings' do
       expect(subject.parameters(mock_request, nil)).to eq(params: {
diff --git a/spec/lib/grape_logging/loggers/request_headers_spec.rb b/spec/lib/grape_logging/loggers/request_headers_spec.rb
index f34e9b7..dd749f6 100644
--- a/spec/lib/grape_logging/loggers/request_headers_spec.rb
+++ b/spec/lib/grape_logging/loggers/request_headers_spec.rb
@@ -1,23 +1,22 @@
 require 'spec_helper'
-require 'ostruct'
 
 describe GrapeLogging::Loggers::RequestHeaders do
   let(:mock_request) do
-    OpenStruct.new(env: { HTTP_REFERER: 'http://example.com', HTTP_ACCEPT: 'text/plain' })
+    instance_double(Rack::Request, env: { HTTP_REFERER: 'http://example.com', HTTP_ACCEPT: 'text/plain' })
   end
 
   let(:mock_request_with_unhandled_headers) do
-    OpenStruct.new(env: {
-                     HTTP_REFERER: 'http://example.com',
-                     'PATH_INFO' => '/api/v1/users'
-                   })
+    instance_double(Rack::Request, env: {
+                      HTTP_REFERER: 'http://example.com',
+                      'PATH_INFO' => '/api/v1/users'
+                    })
   end
 
   let(:mock_request_with_long_headers) do
-    OpenStruct.new(env: {
-                     HTTP_REFERER: 'http://example.com',
-                     HTTP_USER_AGENT: 'Mozilla/5.0'
-                   })
+    instance_double(Rack::Request, env: {
+                      HTTP_REFERER: 'http://example.com',
+                      HTTP_USER_AGENT: 'Mozilla/5.0'
+                    })
   end
 
   it 'strips HTTP_ from the parameter' do
diff --git a/spec/lib/grape_logging/loggers/response_spec.rb b/spec/lib/grape_logging/loggers/response_spec.rb
index c446135..4990c5c 100644
--- a/spec/lib/grape_logging/loggers/response_spec.rb
+++ b/spec/lib/grape_logging/loggers/response_spec.rb
@@ -1,10 +1,9 @@
 require 'spec_helper'
-require 'ostruct'
 
 describe GrapeLogging::Loggers::Response do
   context 'with a parseable JSON body' do
     let(:response) do
-      OpenStruct.new(body: [{ one: 'two', three: { four: 5 } }])
+      instance_double(Rack::Request, body: [{ one: 'two', three: { four: 5 } }])
     end
 
     it 'returns an array of parsed JSON objects' do
@@ -14,7 +13,7 @@
 
   context 'with a body that is not parseable JSON' do
     let(:response) do
-      OpenStruct.new(body: 'this is a body')
+      instance_double(Rack::Request, body: 'this is a body')
     end
 
     it 'just returns the body' do