diff --git a/.travis.yml b/.travis.yml
index cebc673..76435dd 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,48 +1,35 @@
 language: ruby
 cache: bundler
-# To use rbx environment.
 dist: trusty
-rvm:
-  - 2.2
-  - 2.3
-  - 2.4
-  - 2.5
-  - 2.6
-  - ruby-head
-  - jruby-9.2.6.0
-  - rbx-3
-gemfile:
-  - Gemfile
-  - gemfiles/Gemfile-5-2-stable
 matrix:
-  exclude:
-    - gemfile: Gemfile
   include:
     - gemfile: Gemfile
-      rvm: 2.5
-    - gemfile: Gemfile
-      rvm: 2.6
+      rvm: 2.7
     - gemfile: Gemfile
       rvm: ruby-head
-    - gemfile: Gemfile
-      rvm: rbx-3
+
+    - gemfile: gemfiles/Gemfile-6-1-stable
+      rvm: 2.7
+    - gemfile: gemfiles/Gemfile-6-1-stable
+      rvm: 2.6
+    - gemfile: gemfiles/Gemfile-6-1-stable
+      rvm: 2.5
+
+    - gemfile: gemfiles/Gemfile-6-0-stable
+      rvm: 2.6
+    - gemfile: gemfiles/Gemfile-6-0-stable
+      rvm: 2.5
+    - gemfile: gemfiles/Gemfile-6-0-stable
+      rvm: jruby-9.2.6.0
+
     - gemfile: gemfiles/Gemfile-5-2-stable
       rvm: 2.2
     - gemfile: gemfiles/Gemfile-5-2-stable
       rvm: 2.3
     - gemfile: gemfiles/Gemfile-5-2-stable
       rvm: 2.4
-    - gemfile: gemfiles/Gemfile-5-2-stable
-      rvm: 2.5
-    - gemfile: gemfiles/Gemfile-5-2-stable
-      rvm: 2.6
-    - gemfile: gemfiles/Gemfile-5-2-stable
-      rvm: ruby-head
-    - gemfile: gemfiles/Gemfile-5-2-stable
-      rvm: rbx-3
   allow_failures:
     - rvm: ruby-head
-    - rvm: rbx-3
   fast_finish: true
 notifications:
   email: false
diff --git a/Gemfile b/Gemfile
index 371e9b8..2b629e2 100644
--- a/Gemfile
+++ b/Gemfile
@@ -3,4 +3,4 @@ source "https://rubygems.org"
 # Specify your gem's dependencies in coffee-rails.gemspec
 gemspec
 
-gem 'rails', git: 'https://github.com/rails/rails'
+gem 'rails', git: 'https://github.com/rails/rails', ref: 'main'
diff --git a/gemfiles/Gemfile-6-0-stable b/gemfiles/Gemfile-6-0-stable
new file mode 100644
index 0000000..fc492e7
--- /dev/null
+++ b/gemfiles/Gemfile-6-0-stable
@@ -0,0 +1,6 @@
+source "https://rubygems.org"
+
+gemspec path: '..'
+
+gem 'rails', git: 'https://github.com/rails/rails', ref: '6-0-stable'
+
diff --git a/gemfiles/Gemfile-6-1-stable b/gemfiles/Gemfile-6-1-stable
new file mode 100644
index 0000000..1834e9d
--- /dev/null
+++ b/gemfiles/Gemfile-6-1-stable
@@ -0,0 +1,6 @@
+source "https://rubygems.org"
+
+gemspec path: '..'
+
+gem 'rails', git: 'https://github.com/rails/rails', ref: '6-1-stable'
+