diff --git a/lib/paperclip.rb b/lib/paperclip.rb
index 34b290f27..de883e118 100644
--- a/lib/paperclip.rb
+++ b/lib/paperclip.rb
@@ -56,6 +56,7 @@
 require 'paperclip/attachment_registry'
 require 'paperclip/filename_cleaner'
 require 'paperclip/rails_environment'
+require "paperclip/deprecations"
 
 begin
   # Use mime/types/columnar if available, for reduced memory usage
@@ -191,6 +192,7 @@ module ClassMethods
     #     end
     #   end
     def has_attached_file(name, options = {})
+      Paperclip::Deprecations.check
       HasAttachedFile.define_on(self, name, options)
     end
   end
diff --git a/lib/paperclip/deprecations.rb b/lib/paperclip/deprecations.rb
new file mode 100644
index 000000000..1495145d7
--- /dev/null
+++ b/lib/paperclip/deprecations.rb
@@ -0,0 +1,42 @@
+require "active_support/deprecation"
+
+module Paperclip
+  class Deprecations
+    class << self
+      def check
+        warn_aws_sdk_v1 if aws_sdk_v1?
+        warn_outdated_rails if active_model_version < "4.2"
+      end
+
+      private
+
+      def active_model_version
+        ::ActiveModel::VERSION::STRING
+      end
+
+      def aws_sdk_v1?
+        defined?(::AWS) && aws_sdk_version < "2"
+      end
+
+      def warn_aws_sdk_v1
+        warn "[paperclip] [deprecation] AWS SDK v1 has been deprecated in " \
+             "paperclip 5. Please consider upgrading to AWS 2 before " \
+             "upgrading paperclip."
+      end
+
+      def warn_outdated_rails
+        warn "[paperclip] [deprecation] Rails 3.2 and 4.1 are unsupported as " \
+             "of Rails 5 release. Please upgrade to Rails 4.2 before " \
+             "upgrading paperclip."
+      end
+
+      def aws_sdk_version
+        ::AWS::VERSION
+      end
+
+      def warn(message)
+        ActiveSupport::Deprecation.warn(message)
+      end
+    end
+  end
+end
diff --git a/spec/paperclip/deprecations_spec.rb b/spec/paperclip/deprecations_spec.rb
new file mode 100644
index 000000000..efcb44c35
--- /dev/null
+++ b/spec/paperclip/deprecations_spec.rb
@@ -0,0 +1,65 @@
+require "spec_helper"
+require "aws-sdk"
+require "active_support/testing/deprecation"
+
+describe Paperclip::Deprecations do
+  include ActiveSupport::Testing::Deprecation
+
+  describe ".check" do
+    before do
+      ActiveSupport::Deprecation.silenced = false
+    end
+
+    after do
+      ActiveSupport::Deprecation.silenced = true
+    end
+
+    context "when active model version is < 4.2" do
+      it "displays deprecation warning" do
+        Paperclip::Deprecations.stubs(:active_model_version).returns("4.1")
+
+        assert_deprecated("Rails 3.2 and 4.1 are unsupported") do
+          Paperclip::Deprecations.check
+        end
+      end
+    end
+
+    context "when active model version is 4.2" do
+      it "do not display deprecation warning" do
+        Paperclip::Deprecations.stubs(:active_model_version).returns("4.2")
+
+        assert_not_deprecated do
+          Paperclip::Deprecations.check
+        end
+      end
+    end
+
+    context "when aws sdk version is < 2" do
+      before do
+        ::AWS.stub! if !defined?(::AWS)
+      end
+
+      it "displays deprecation warning" do
+        Paperclip::Deprecations.stubs(:aws_sdk_version).returns("1.68.0")
+
+        assert_deprecated("AWS SDK v1 has been deprecated") do
+          Paperclip::Deprecations.check
+        end
+      end
+    end
+
+    context "when aws sdk version is 2" do
+      before do
+        ::AWS.stub! if !defined?(::AWS)
+      end
+
+      it "do not display deprecation warning" do
+        Paperclip::Deprecations.stubs(:aws_sdk_version).returns("2.0.0")
+
+        assert_not_deprecated do
+          Paperclip::Deprecations.check
+        end
+      end
+    end
+  end
+end
diff --git a/spec/paperclip/paperclip_spec.rb b/spec/paperclip/paperclip_spec.rb
index c47dfdbc6..5e2d4a665 100644
--- a/spec/paperclip/paperclip_spec.rb
+++ b/spec/paperclip/paperclip_spec.rb
@@ -109,6 +109,7 @@ class ::Four; end
 
   context "An ActiveRecord model with an 'avatar' attachment" do
     before do
+      Paperclip::Deprecations.stubs(:check)
       rebuild_model path: "tmp/:class/omg/:style.:extension"
       @file = File.new(fixture_file("5k.png"), 'rb')
     end
@@ -150,6 +151,10 @@ class ::Four; end
       end
     end
 
+    it "calls Paperclip::Deprecations.check" do
+      expect(Paperclip::Deprecations).to have_received(:check)
+    end
+
     context "with a subclass" do
       before do
         class ::SubDummy < Dummy; end
diff --git a/spec/support/deprecations.rb b/spec/support/deprecations.rb
new file mode 100644
index 000000000..594fd6f14
--- /dev/null
+++ b/spec/support/deprecations.rb
@@ -0,0 +1,9 @@
+RSpec.configure do |config|
+  config.before(:all) do
+    ActiveSupport::Deprecation.silenced = true
+  end
+  config.before(:each) do
+    Paperclip::Deprecations.stubs(:active_model_version).returns("4.2")
+    Paperclip::Deprecations.stubs(:aws_sdk_version).returns("2.0.0")
+  end
+end