diff --git a/rubygem-activesupport-5.2.1-update-I18n-fallbacks-configuration.patch b/rubygem-activesupport-5.2.1-update-I18n-fallbacks-configuration.patch
new file mode 100644
index 0000000..3ef8ca7
--- /dev/null
+++ b/rubygem-activesupport-5.2.1-update-I18n-fallbacks-configuration.patch
@@ -0,0 +1,37 @@
+From 66614f6b67402ec526a699760d1c21c586834da8 Mon Sep 17 00:00:00 2001
+From: Lachlan Sylvester <lachlan.sylvester@publicisfrontfoot.com.au>
+Date: Fri, 10 Aug 2018 14:28:40 +1000
+Subject: [PATCH] update I18n fallbacks configuration to be compatible with
+ i18n 1.1.0
+
+---
+ activesupport/lib/active_support/i18n_railtie.rb | 14 +++++++++++++-
+ 1 files changed, 13 insertions(+), 1 deletions(-)
+
+diff --git a/activesupport/lib/active_support/i18n_railtie.rb b/activesupport/lib/active_support/i18n_railtie.rb
+index 93bde57f6aa6..c07eb5b56986 100644
+--- a/activesupport/lib/active_support/i18n_railtie.rb
++++ b/activesupport/lib/active_support/i18n_railtie.rb
+@@ -88,9 +88,21 @@ def self.init_fallbacks(fallbacks)
+         when Hash, Array
+           Array.wrap(fallbacks)
+         else # TrueClass
+-          []
++          [I18n.default_locale]
+         end
+ 
++      if args.empty? || args.first.is_a?(Hash)
++        ActiveSupport::Deprecation.warn(<<-MSG.squish)
++          Using I18n fallbacks with an empty `defaults` sets the defaults to
++          include the `default_locale`. This behavior will change in Rails 6.1.
++          If you desire the default local to be included in the defaults, please
++          explicitly configure it with `config.i18n.fallbacks.defaults =
++          [I18n.default_locale]` or `config.i18n.fallbacks = [I18n.default_locale,
++          {...}]`
++        MSG
++        args.unshift I18n.default_locale
++      end
++
+       I18n.fallbacks = I18n::Locale::Fallbacks.new(*args)
+     end
+ 
diff --git a/rubygem-activesupport.spec b/rubygem-activesupport.spec
index d3e51d3..f34b9d6 100644
--- a/rubygem-activesupport.spec
+++ b/rubygem-activesupport.spec
@@ -3,7 +3,7 @@
 Name: rubygem-%{gem_name}
 Epoch: 1
 Version: 5.2.1
-Release: 1%{?dist}
+Release: 2%{?dist}
 Summary: A support libraries and Ruby core extensions extracted from the Rails framework
 License: MIT
 URL: http://rubyonrails.org
@@ -16,6 +16,10 @@ Source0: https://rubygems.org/gems/%{gem_name}-%{version}.gem
 # git checkout v5.2.1 && tar czvf activesupport-5.2.1-tests.tgz test/
 Source1: %{gem_name}-%{version}-tests.tgz
 
+# Update I18n fallbacks configuration to be compatible with i18n 1.1.0.
+# https://github.com/rails/rails/pull/33574
+Patch0: rubygem-activesupport-5.2.1-update-I18n-fallbacks-configuration.patch
+
 # ruby package has just soft dependency on rubygem({bigdecimal,json}), while
 # ActiveSupport always requires them.
 Requires: rubygem(bigdecimal)
@@ -56,6 +60,8 @@ Documentation for %{name}.
 %prep
 %setup -q -n %{gem_name}-%{version}
 
+%patch0 -p2
+
 %build
 gem build ../%{gem_name}-%{version}.gemspec
 
@@ -103,6 +109,9 @@ popd
 %doc %{gem_instdir}/README.rdoc
 
 %changelog
+* Wed Nov 14 2018 Vít Ondruch <vondruch@redhat.com> - 1:5.2.1-2
+- Update I18n fallbacks configuration to be compatible with i18n 1.1.0.
+
 * Wed Aug 08 2018 Pavel Valena <pvalena@redhat.com> - 1:5.2.1-1
 - Update to Active Support 5.2.1.