diff --git a/middleman-core/lib/middleman-core/application.rb b/middleman-core/lib/middleman-core/application.rb
index ba9eef9b..6b32c03a 100644
--- a/middleman-core/lib/middleman-core/application.rb
+++ b/middleman-core/lib/middleman-core/application.rb
@@ -4,6 +4,10 @@ require "tilt"
 # i18n Built-in
 require "i18n"
 
+# Don't fail on invalid locale, that's not what our current
+# users expect.
+::I18n.config.enforce_available_locales = false
+
 # Use ActiveSupport JSON
 require "active_support/json"
 require "active_support/core_ext/integer/inflections"
diff --git a/middleman-core/middleman-core.gemspec b/middleman-core/middleman-core.gemspec
index 25a231ec..954a2325 100644
--- a/middleman-core/middleman-core.gemspec
+++ b/middleman-core/middleman-core.gemspec
@@ -36,5 +36,5 @@ Gem::Specification.new do |s|
   s.add_dependency("listen", ["~> 1.1"])
 
   # i18n
-  s.add_dependency("i18n", ["~> 0.6.1"])
+  s.add_dependency("i18n", ["~> 0.6.9"])
 end