.travis.yml in redis-4.0.0.rc1 vs .travis.yml in redis-4.0.0

@@ -1,23 +1,23 @@
 language: ruby
 
 script: make test
 
-before_install:
-  - rvm get stable
-
 rvm:
-  - 2.1
-  - 2.2
-  - 2.3
+  - 2.2.2
+  - 2.3.3
+  - 2.4.1
   - jruby-9
   - rbx-3
 
 gemfile: ".travis/Gemfile"
 
 sudo: false
 
+before_script:
+- if (ruby -e "exit RUBY_VERSION.to_f >= 2.4"); then export RUBYOPT="--enable-frozen-string-literal"; fi; echo $RUBYOPT
+
 env:
   global:
     - VERBOSE=true
     - TIMEOUT=1
   matrix:
@@ -29,9 +29,11 @@
     - DRIVER=synchrony REDIS_BRANCH=3.2
     - DRIVER=ruby      REDIS_BRANCH=unstable
 
 branches:
   only:
+    - staging
+    - trying
     - master
 
 matrix:
   exclude:
     # hiredis