diff --git a/Gemfile.lock b/Gemfile.lock
index c992783..715e46c 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -2,7 +2,7 @@ PATH
   remote: .
   specs:
     lean-microsoft-graph (0.4.0)
-      base64 (~> 0.2.0)
+      base64 (>= 0.2, < 0.4)
       faraday (~> 2.0)
       faraday-retry (~> 2.0)
       logger (~> 1.6)
@@ -10,7 +10,7 @@ PATH
 GEM
   remote: https://rubygems.org/
   specs:
-    base64 (0.2.0)
+    base64 (0.3.0)
     faraday (2.0.0)
       ruby2_keywords (>= 0.0.4)
     faraday-retry (2.3.2)
diff --git a/lean-microsoft-graph.gemspec b/lean-microsoft-graph.gemspec
index e4379c2..60c695a 100644
--- a/lean-microsoft-graph.gemspec
+++ b/lean-microsoft-graph.gemspec
@@ -29,7 +29,7 @@ Gem::Specification.new do |spec|
   spec.executables = spec.files.grep(%r{\Aexe/}) { |f| File.basename(f) }
   spec.require_paths = ['lib']
 
-  spec.add_dependency 'base64', '~> 0.2.0'
+  spec.add_dependency 'base64', '>= 0.2', '< 0.4'
   spec.add_dependency 'faraday', '~> 2.0'
   spec.add_dependency 'faraday-retry', '~> 2.0'
   spec.add_dependency 'logger', '~> 1.6'