diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2c4fc3f9..c3178147 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,8 @@
 # Changelog
 
+## Unreleased
+- Add gems that are no longer standard libraries / default gems to Gemfile and gemspec
+
 ## 4.33.1
 - Bug fix for Nokogiri XML parsing
 
diff --git a/Gemfile b/Gemfile
index 0311acdf..df3ae0d4 100644
--- a/Gemfile
+++ b/Gemfile
@@ -3,6 +3,10 @@ source "https://rubygems.org"
 gem "builder", "3.2.4"
 gem "nokogiri", "~> 1.12"
 gem "require_all", "3.0.0"
+gem "base64", ">= 0.3.0"
+gem "bigdecimal", ">= 3.3.1"
+gem "logger", ">= 1.7.0"
+gem "ostruct", ">= 0.6.3"
 
 group :development do
   gem "pry", "0.13.1"
diff --git a/braintree.gemspec b/braintree.gemspec
index adb5cc15..b13ba6e1 100644
--- a/braintree.gemspec
+++ b/braintree.gemspec
@@ -13,6 +13,10 @@ Gem::Specification.new do |s|
   s.files = Dir.glob ["README.rdoc", "LICENSE", "lib/**/*.{rb,crt}", "spec/**/*", "*.gemspec"]
   s.add_dependency "builder", ">= 3.2.4"
   s.add_dependency "rexml", ">= 3.1.9" # Use rexml version associated with minimum supported Ruby version
+  s.add_dependency "base64", ">= 0.3.0"
+  s.add_dependency "bigdecimal", ">= 3.3.1"
+  s.add_dependency "logger", ">= 1.7.0"
+  s.add_dependency "ostruct", ">= 0.6.3"
   s.required_ruby_version = ">=2.6.0"
   s.metadata = {
     "bug_tracker_uri" => "https://github.com/braintree/braintree_ruby/issues",