.travis.yml in icalendar-recurrence-1.1.1 vs .travis.yml in icalendar-recurrence-1.1.2

@@ -1,6 +1,9 @@
 language: ruby
+sudo: false
 rvm:
-  - 2.1.0
+  - 2.4.1
+  - 2.3.4
+  - 2.1.7
   - 2.0.0
   - 1.9.3
-script: bundle exec rspec
\ No newline at end of file
+script: bundle exec rspec