diff --git a/Gemfile b/Gemfile
index 43046e4..ffe2946 100644
--- a/Gemfile
+++ b/Gemfile
@@ -2,16 +2,16 @@ source ENV['GEM_SOURCE'] || 'https://rubygems.org'
 
 gem 'json', '>= 1.8'
 gem 'pickup', '~> 0.0.11'
-gem 'puma', '~> 3.11'
-gem 'rack', '~> 2.0'
+gem 'puma', '~> 4.3'
+gem 'rack', '~> 2.2'
 gem 'rake', '~> 12.3'
-gem 'redis', '~> 4.0'
-gem 'rbvmomi', '~> 1.13'
+gem 'redis', '~> 4.1'
+gem 'rbvmomi', '~> 2.1'
 gem 'sinatra', '~> 2.0'
 gem 'net-ldap', '~> 0.16'
 gem 'statsd-ruby', '~> 1.4.0', :require => 'statsd'
 gem 'connection_pool', '~> 2.2'
-gem 'nokogiri', '~> 1.8'
+gem 'nokogiri', '~> 1.10'
 gem 'spicy-proton', '~> 2.1'
 
 group :development do
diff --git a/vmpooler.gemspec b/vmpooler.gemspec
index 596218f..b101a02 100644
--- a/vmpooler.gemspec
+++ b/vmpooler.gemspec
@@ -18,15 +18,15 @@ Gem::Specification.new do |s|
   s.executables   = 'vmpooler'
   s.require_paths = ["lib"]
   s.add_dependency 'pickup', '~> 0.0.11'
-  s.add_dependency 'puma', '~> 3.11'
-  s.add_dependency 'rack', '~> 2.0'
+  s.add_dependency 'puma', '~> 4.3'
+  s.add_dependency 'rack', '~> 2.2'
   s.add_dependency 'rake', '~> 12.3'
-  s.add_dependency 'redis', '~> 4.0'
-  s.add_dependency 'rbvmomi', '~> 1.13'
+  s.add_dependency 'redis', '~> 4.1'
+  s.add_dependency 'rbvmomi', '~> 2.1'
   s.add_dependency 'sinatra', '~> 2.0'
   s.add_dependency 'net-ldap', '~> 0.16'
   s.add_dependency 'statsd-ruby', '~> 1.4'
   s.add_dependency 'connection_pool', '~> 2.2'
-  s.add_dependency 'nokogiri', '~> 1.8'
+  s.add_dependency 'nokogiri', '~> 1.10'
   s.add_dependency 'spicy-proton', '~> 2.1'
 end