diff --git a/.ruby-version b/.ruby-version
index 437459c..75a22a2 100644
--- a/.ruby-version
+++ b/.ruby-version
@@ -1 +1 @@
-2.5.0
+3.0.3
diff --git a/lib/swagger/diff/specification.rb b/lib/swagger/diff/specification.rb
index c023736..e7f044b 100644
--- a/lib/swagger/diff/specification.rb
+++ b/lib/swagger/diff/specification.rb
@@ -53,7 +53,7 @@ def parse_swagger(swagger)
           swagger
         else
           if File.exist?(swagger) || swagger[0..7] =~ %r{^https?://}
-            swagger = open(swagger).read
+            swagger = File.exist?(swagger) ? open(swagger).read : URI.open(swagger).read
           end
           begin
             JSON.parse(swagger)
diff --git a/swagger-diff.gemspec b/swagger-diff.gemspec
index 853aad5..1e6689d 100644
--- a/swagger-diff.gemspec
+++ b/swagger-diff.gemspec
@@ -25,15 +25,15 @@ Gem::Specification.new do |spec|
   spec.executables   = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }
   spec.require_paths = ['lib']
 
-  spec.required_ruby_version = '~> 2.0'
+  spec.required_ruby_version = '>= 2.0'
 
-  spec.add_dependency 'json-schema', '~> 2.6'
-  spec.add_dependency 'rspec-expectations', '~> 3.3'
-  spec.add_development_dependency 'bundler', '~> 1.9'
-  spec.add_development_dependency 'pry', '~> 0.11.3'
-  spec.add_development_dependency 'rake', '~> 12.3'
-  spec.add_development_dependency 'rspec', '~> 3.3'
-  spec.add_development_dependency 'rubocop', '~> 0.49.0'
-  spec.add_development_dependency 'vcr', '~> 4.0'
-  spec.add_development_dependency 'webmock', '~> 3.0'
+  spec.add_dependency 'json-schema', '~> 2.8.1'
+  spec.add_dependency 'rspec-expectations', '~> 3.11.0'
+  spec.add_development_dependency 'bundler', '~> 2.3.9'
+  spec.add_development_dependency 'pry', '~> 0.14.1'
+  spec.add_development_dependency 'rake', '~> 13.0.6'
+  spec.add_development_dependency 'rspec', '~> 3.11.0'
+  spec.add_development_dependency 'rubocop', '~> 1.26.1'
+  spec.add_development_dependency 'vcr', '~> 6.1.0'
+  spec.add_development_dependency 'webmock', '~> 3.14.0'
 end