diff --git a/.travis.yml b/.travis.yml
index 53e6c1e..0fe030c 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,8 +1,11 @@
+sudo: false
 language: ruby
 rvm:
-  - "1.9.2"
   - "1.9.3"
   - "2.0.0"
+  - "2.2"
+  - "2.3"
+  - "2.4"
   - jruby-19mode # JRuby in 1.9 mode
 #   - "1.8.7"
 #   - jruby-18mode # JRuby in 1.8 mode
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5a03026..0df3482 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,6 @@
+# 1.2.0
+* Remove ruby Bignum
+
 # 1.0.2
 * Handle numbers with M precision
 
diff --git a/lib/edn/core_ext.rb b/lib/edn/core_ext.rb
index 316ce2c..41e7e2c 100644
--- a/lib/edn/core_ext.rb
+++ b/lib/edn/core_ext.rb
@@ -16,12 +16,6 @@ def allows_metadata?
       end
     end
 
-    module Bignum
-      def to_edn
-        self.to_s + 'M'
-      end
-    end
-
     module BigDecimal
       def to_edn
         self.to_s('F') + 'M'
@@ -90,11 +84,20 @@ def to_edn
         EDN.tagout("inst", self.xmlschema)
       end
     end
+
+    if RUBY_VERSION >= '2.4.0'
+      module Bignum
+        def to_edn
+          self.to_s + 'M'
+        end
+      end
+      ::Bignum.send(:include, EDN::CoreExt::Bignum)
+    end
+
   end
 end
 
 Numeric.send(:include, EDN::CoreExt::Unquoted)
-Bignum.send(:include, EDN::CoreExt::Bignum)
 BigDecimal.send(:include, EDN::CoreExt::BigDecimal)
 TrueClass.send(:include, EDN::CoreExt::Unquoted)
 FalseClass.send(:include, EDN::CoreExt::Unquoted)
diff --git a/lib/edn/version.rb b/lib/edn/version.rb
index 5c9d1c8..5b15ee6 100644
--- a/lib/edn/version.rb
+++ b/lib/edn/version.rb
@@ -1,3 +1,3 @@
 module EDN
-  VERSION = "1.1.1"
+  VERSION = "1.2.0"
 end