diff --git a/CHANGELOG.md b/CHANGELOG.md
index 501f65ba..4609b848 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # CHANGELOG
 
+## 3.11.8 - 2021-07-03
+
+- Fixed or reverted change that set the default mode when optimize_Rails was called.
+
 ## 3.11.7 - 2021-06-22
 
 - Fixed exception type when parsing after `Oj::Rails.mimic_JSON` is called.
diff --git a/ext/oj/rails.c b/ext/oj/rails.c
index 56ab59bc..f59d6f27 100644
--- a/ext/oj/rails.c
+++ b/ext/oj/rails.c
@@ -828,7 +828,8 @@ rails_mimic_json(VALUE self) {
         json = rb_define_module("JSON");
     }
     oj_mimic_json_methods(json);
-    oj_default_options.mode = RailsMode;
+    // Setting the default mode breaks the prmoise in the docs not to.
+    //oj_default_options.mode = RailsMode;
 
     return Qnil;
 }