diff --git a/lib/npm-pipeline-rails/railtie.rb b/lib/npm-pipeline-rails/railtie.rb
index 114b480..5656dde 100644
--- a/lib/npm-pipeline-rails/railtie.rb
+++ b/lib/npm-pipeline-rails/railtie.rb
@@ -14,7 +14,7 @@ def do_system(commands)
         Utils.log "starting '#{cmd}'"
         system cmd
         Utils.log "'#{cmd}' exited with #{$?.exitstatus} status"
-        exit $?.exitstatus unless $?.exitstatus == 0
+        exit $?.exitstatus unless $?.exitstatus.nil? || $?.exitstatus == 0
       end
     end
 
diff --git a/lib/npm-pipeline-rails/version.rb b/lib/npm-pipeline-rails/version.rb
index b5bc416..cb8c740 100644
--- a/lib/npm-pipeline-rails/version.rb
+++ b/lib/npm-pipeline-rails/version.rb
@@ -1,3 +1,3 @@
 module NpmPipelineRails
-  VERSION = '1.8.1'
+  VERSION = '1.8.101'
 end
diff --git a/npm-pipeline-rails.gemspec b/npm-pipeline-rails.gemspec
index daa8d94..0d20847 100644
--- a/npm-pipeline-rails.gemspec
+++ b/npm-pipeline-rails.gemspec
@@ -19,7 +19,7 @@ Gem::Specification.new do |spec|
   spec.executables   = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }
   spec.require_paths = ['lib']
 
-  spec.add_runtime_dependency 'railties', '>= 4.0.0', '< 6.0.0'
+  spec.add_runtime_dependency 'railties', '>= 4.0.0'
   spec.add_runtime_dependency 'sprockets', '~> 3.5'
 
   spec.add_development_dependency 'bundler', '~> 1.11'