diff --git a/.rubocop.yml b/.rubocop.yml
index e3cf91c..01cd170 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -1,7 +1,7 @@
 ---
 
 AllCops:
-  TargetRubyVersion: 2.1
+  TargetRubyVersion: 2.3
 
 Metrics/LineLength:
   Max: 140
diff --git a/README.md b/README.md
index f50d75e..994ca85 100644
--- a/README.md
+++ b/README.md
@@ -22,7 +22,7 @@ And then execute:
 
 ### CLI
 
-After installation, 2 executeable scripts will be installed: `smps` & `smps-cli`:
+After installation, 2 executable scripts will be installed: `smps` & `smps-cli`:
 
 - smps: the simple version of this utility.
 - smps-cli: The thor cli executable offers a different interface.
@@ -122,10 +122,12 @@ Set the parameter to this value
 
 ## Development
 
-After checking out the repo, run `bin/setup` to install dependencies. Then, run `rake spec` to run the tests. You can also run `bin/console` for an interactive prompt that will allow you to experiment.
+After checking out the repo, run `./bin/setup` to install dependencies. Then, run `bundle exec rake spec` to run the tests. You can also run `bin/console` for an interactive prompt that will allow you to experiment.
 
 To install this gem onto your local machine, run `bundle exec rake install`. To release a new version, update the version number in `version.rb`, and then run `bundle exec rake release`, which will create a git tag for the version, push git commits and tags, and push the `.gem` file to [rubygems.org](https://rubygems.org).
 
+To test the `smps` utility on your local machine, run `bundle exec smps --help` to see command-line options.
+
 ## Contributing
 
 We use git flow in this project. To create your pull request, you can either use the git-flow helper or
diff --git a/Rakefile b/Rakefile
index 2d5637f..e8a19a4 100644
--- a/Rakefile
+++ b/Rakefile
@@ -43,9 +43,9 @@ end
 desc 'Tags version, pushes to remote, and pushes gem'
 task release: :build do
   sh 'git', 'tag', '-m', changelog, "v#{SmPs::VERSION}"
-  #sh 'git push origin master'
-  #sh "git push origin v#{SmPs::VERSION}"
-  #sh 'ls pkg/*.gem | xargs -n 1 gem push'
+  # sh 'git push origin master'
+  # sh "git push origin v#{SmPs::VERSION}"
+  # sh 'ls pkg/*.gem | xargs -n 1 gem push'
 end
 
 task doc: :yard
diff --git a/changelog.md b/changelog.md
index b456254..6efb987 100644
--- a/changelog.md
+++ b/changelog.md
@@ -5,6 +5,12 @@ Version format based on http://semver.org/
 
 ## [Unreleased]
 
+## [0.5.4] - 2021-09-17
+
+### Changed
+
+- Added automatic client side throttling to avoid Aws::SSM::Errors::ThrottlingException.
+
 ## [0.5.3] - 2020-04-01
 
 ### Changed
diff --git a/lib/smps/client.rb b/lib/smps/client.rb
index 9f67bd7..c7639e2 100644
--- a/lib/smps/client.rb
+++ b/lib/smps/client.rb
@@ -9,7 +9,7 @@ module SmPs
   # Allows querying and writing Paramstore parameters.
   class Client
     def initialize(options = {})
-      @credentials = options[:credentials]
+      @options = options
       @parameters = {}
     end
 
@@ -90,11 +90,11 @@ def store_parameters(params)
     # end
 
     def initialize_ssm_client
-      if @credentials.nil?
-        Aws::SSM::Client.new
-      else
-        Aws::SSM::Client.new(credentials: @credentials)
-      end
+      # see https://docs.aws.amazon.com/sdk-for-ruby/v3/api/Aws/SSM/Client.html#initialize-instance_method
+      all_options = @options.merge(max_attempts: 10,
+                                   retry_mode: 'adaptive')
+      # puts all_options
+      Aws::SSM::Client.new(all_options)
     end
   end
 end
diff --git a/lib/smps/version.rb b/lib/smps/version.rb
index 78f4a95..3333f87 100644
--- a/lib/smps/version.rb
+++ b/lib/smps/version.rb
@@ -2,5 +2,5 @@
 
 module SmPs
   # Current version.
-  VERSION = '0.5.3'
+  VERSION = '0.5.4'
 end
diff --git a/smps.gemspec b/smps.gemspec
index 425a138..024420e 100644
--- a/smps.gemspec
+++ b/smps.gemspec
@@ -37,5 +37,5 @@ Gem::Specification.new do |spec|
   spec.add_runtime_dependency 'aws-sdk-core', '> 3.0'
   spec.add_runtime_dependency 'aws-sdk-ssm', '> 1.0'
 
-  spec.required_ruby_version = '>= 2.1'
+  spec.required_ruby_version = '>= 2.3'
 end