diff --git a/lib/bugsnag.rb b/lib/bugsnag.rb
index 06273b318..2fbcd2d9f 100644
--- a/lib/bugsnag.rb
+++ b/lib/bugsnag.rb
@@ -34,7 +34,8 @@ def configure
 
     # Explicitly notify of an exception
     def notify(exception, auto_notify=false, &block)
-      if auto_notify && !configuration.auto_notify
+      
+      if !configuration.auto_notify && auto_notify
         configuration.debug("Not notifying because auto_notify is disabled")
         return
       end
@@ -49,7 +50,7 @@ def notify(exception, auto_notify=false, &block)
         return
       end
 
-      report = Report.new(exception, configuration)
+      report = Report.new(exception, configuration, auto_notify)     
 
       # If this is an auto_notify we yield the block before the any middleware is run
       yield(report) if block_given? && auto_notify
@@ -65,6 +66,10 @@ def notify(exception, auto_notify=false, &block)
         return
       end
 
+      # Store before_middleware severity reason for future reference
+      initial_severity = report.severity
+      initial_reason = report.severity_reason
+
       # Run users middleware
       configuration.middleware.run(report) do
         if report.ignore?
@@ -80,6 +85,15 @@ def notify(exception, auto_notify=false, &block)
           return
         end
 
+        # Test whether severity has been changed and ensure severity_reason is consistant in auto_notify case
+        if report.severity != initial_severity
+          report.severity_reason = {
+            :type => Bugsnag::Report::USER_CALLBACK_SET_SEVERITY
+          }
+        else
+          report.severity_reason = initial_reason
+        end
+
         # Deliver
         configuration.info("Notifying #{configuration.endpoint} of #{report.exceptions.last[:errorClass]}")
         payload_string = ::JSON.dump(Bugsnag::Helpers.trim_if_needed(report.as_json))
diff --git a/lib/bugsnag/configuration.rb b/lib/bugsnag/configuration.rb
index 38b23e4cc..cb922a356 100644
--- a/lib/bugsnag/configuration.rb
+++ b/lib/bugsnag/configuration.rb
@@ -5,6 +5,7 @@
 require "bugsnag/middleware/callbacks"
 require "bugsnag/middleware/exception_meta_data"
 require "bugsnag/middleware/ignore_error_class"
+require "bugsnag/middleware/classify_error"
 
 module Bugsnag
   class Configuration
@@ -73,6 +74,7 @@ def initialize
       self.internal_middleware = Bugsnag::MiddlewareStack.new
       self.internal_middleware.use Bugsnag::Middleware::ExceptionMetaData
       self.internal_middleware.use Bugsnag::Middleware::IgnoreErrorClass
+      self.internal_middleware.use Bugsnag::Middleware::ClassifyError
 
       self.middleware = Bugsnag::MiddlewareStack.new
       self.middleware.use Bugsnag::Middleware::Callbacks
diff --git a/lib/bugsnag/integrations/delayed_job.rb b/lib/bugsnag/integrations/delayed_job.rb
index 235ca2098..123badce8 100644
--- a/lib/bugsnag/integrations/delayed_job.rb
+++ b/lib/bugsnag/integrations/delayed_job.rb
@@ -9,6 +9,11 @@
   module Delayed
     module Plugins
       class Bugsnag < Plugin
+
+        FRAMEWORK_ATTRIBUTES = {
+          :framework => "DelayedJob"
+        }
+
         module Notify
           def error(job, error)
             overrides = {
@@ -36,6 +41,10 @@ def error(job, error)
 
             ::Bugsnag.notify(error, true) do |report|
               report.severity = "error"
+              report.severity_reason = {
+                :type => ::Bugsnag::Report::UNHANDLED_EXCEPTION_MIDDLEWARE,
+                :attributes => FRAMEWORK_ATTRIBUTES
+              }
               report.meta_data.merge! overrides
             end
 
diff --git a/lib/bugsnag/integrations/mailman.rb b/lib/bugsnag/integrations/mailman.rb
index c0dc7cd5f..78eeecfd9 100644
--- a/lib/bugsnag/integrations/mailman.rb
+++ b/lib/bugsnag/integrations/mailman.rb
@@ -2,6 +2,11 @@
 
 module Bugsnag
   class Mailman
+
+    FRAMEWORK_ATTRIBUTES = {
+      :framework => "Mailman"
+    }
+
     def initialize
       Bugsnag.configuration.internal_middleware.use(Bugsnag::Middleware::Mailman)
       Bugsnag.configuration.app_type = "mailman"
@@ -15,6 +20,10 @@ def call(mail)
         raise ex if [Interrupt, SystemExit, SignalException].include? ex.class
         Bugsnag.notify(ex, true) do |report|
           report.severity = "error"
+          report.severity_reason = {
+            :type => Bugsnag::Report::UNHANDLED_EXCEPTION_MIDDLEWARE,
+            :attributes => FRAMEWORK_ATTRIBUTES
+          }
         end
         raise
       ensure
diff --git a/lib/bugsnag/integrations/rack.rb b/lib/bugsnag/integrations/rack.rb
index 121628146..b23d78a53 100644
--- a/lib/bugsnag/integrations/rack.rb
+++ b/lib/bugsnag/integrations/rack.rb
@@ -1,5 +1,10 @@
 module Bugsnag
   class Rack
+
+    FRAMEWORK_ATTRIBUTES = {
+      :framework => "Rack"
+    }
+
     def initialize(app)
       @app = app
 
@@ -35,6 +40,10 @@ def call(env)
         # Notify bugsnag of rack exceptions
         Bugsnag.notify(raised, true) do |report|
           report.severity = "error"
+          report.severity_reason = {
+            :type => Bugsnag::Report::UNHANDLED_EXCEPTION_MIDDLEWARE,
+            :attributes => Bugsnag::Rack::FRAMEWORK_ATTRIBUTES
+          }
         end
 
         # Re-raise the exception
@@ -45,6 +54,10 @@ def call(env)
       if env["rack.exception"]
         Bugsnag.notify(env["rack.exception"], true) do |report|
           report.severity = "error"
+          report.severity_reason = {
+            :type => Bugsnag::Report::UNHANDLED_EXCEPTION_MIDDLEWARE,
+            :attributes => FRAMEWORK_ATTRIBUTES
+          }
         end
       end
 
diff --git a/lib/bugsnag/integrations/rails/active_record_rescue.rb b/lib/bugsnag/integrations/rails/active_record_rescue.rb
index aee619ad7..65843e872 100644
--- a/lib/bugsnag/integrations/rails/active_record_rescue.rb
+++ b/lib/bugsnag/integrations/rails/active_record_rescue.rb
@@ -1,6 +1,9 @@
 module Bugsnag::Rails
   module ActiveRecordRescue
     KINDS = [:commit, :rollback].freeze
+    FRAMEWORK_ATTRIBUTES = {
+      :framework => "Rails"
+    }
 
     def run_callbacks(kind, *args, &block)
       if KINDS.include?(kind)
@@ -10,6 +13,10 @@ def run_callbacks(kind, *args, &block)
           # This exception will NOT be escalated, so notify it here.
           Bugsnag.notify(exception, true) do |report|
             report.severity = "error"
+            report.severity_reason = {
+              :type => Bugsnag::Report::UNHANDLED_EXCEPTION_MIDDLEWARE,
+              :attributes => FRAMEWORK_ATTRIBUTES
+            }
           end
           raise
         end
diff --git a/lib/bugsnag/integrations/railtie.rb b/lib/bugsnag/integrations/railtie.rb
index f2047f394..126a4495b 100644
--- a/lib/bugsnag/integrations/railtie.rb
+++ b/lib/bugsnag/integrations/railtie.rb
@@ -7,6 +7,11 @@
 
 module Bugsnag
   class Railtie < Rails::Railtie
+
+    FRAMEWORK_ATTRIBUTES = {
+      :framework => "Rails"
+    }
+
     rake_tasks do
       require "bugsnag/integrations/rake"
       load "bugsnag/tasks/bugsnag.rake"
@@ -19,6 +24,10 @@ class Railtie < Rails::Railtie
           if $!
             Bugsnag.notify($!, true) do |report|
               report.severity = "error"
+              report.severity_reason = {
+                :type => Bugsnag::Report::UNHANDLED_EXCEPTION_MIDDLEWARE,
+                :attributes => FRAMEWORK_ATTRIBUTES
+              }
             end
           end
         end
diff --git a/lib/bugsnag/integrations/rake.rb b/lib/bugsnag/integrations/rake.rb
index a33e5eaea..4756f2c94 100644
--- a/lib/bugsnag/integrations/rake.rb
+++ b/lib/bugsnag/integrations/rake.rb
@@ -4,6 +4,10 @@
 
 class Rake::Task
 
+  FRAMEWORK_ATTRIBUTES = {
+    :framework => "Rake"
+  }
+
   def execute_with_bugsnag(args=nil)
     Bugsnag.configuration.app_type = "rake"
     old_task = Bugsnag.configuration.request_data[:bugsnag_running_task]
@@ -14,6 +18,10 @@ def execute_with_bugsnag(args=nil)
   rescue Exception => ex
     Bugsnag.notify(ex, true) do |report|
       report.severity = "error"
+      report.severity_reason = {
+        :type => Bugsnag::Report::UNHANDLED_EXCEPTION_MIDDLEWARE,
+        :attributes => FRAMEWORK_ATTRIBUTES
+      }
     end
     raise
   ensure
diff --git a/lib/bugsnag/integrations/resque.rb b/lib/bugsnag/integrations/resque.rb
index 9abba7814..409db0e38 100644
--- a/lib/bugsnag/integrations/resque.rb
+++ b/lib/bugsnag/integrations/resque.rb
@@ -3,6 +3,11 @@
 
 module Bugsnag
   class Resque < ::Resque::Failure::Base
+
+    FRAMEWORK_ATTRIBUTES = {
+      :framework => "Resque"
+    }
+
     def self.configure(&block)
       add_failure_backend
       Bugsnag.configure(&block)
@@ -28,6 +33,10 @@ def self.add_failure_backend
     def save
       Bugsnag.notify(exception, true) do |report|
         report.severity = "error"
+        report.severity_reason = {
+          :type => Bugsnag::Report::UNHANDLED_EXCEPTION_MIDDLEWARE,
+          :attributes => FRAMEWORK_ATTRIBUTES
+        }
         report.meta_data.merge!({:context => "#{payload['class']}@#{queue}", :payload => payload, :delivery_method => :synchronous})
       end
     end
diff --git a/lib/bugsnag/integrations/sidekiq.rb b/lib/bugsnag/integrations/sidekiq.rb
index f403afcb1..8239e4b2f 100644
--- a/lib/bugsnag/integrations/sidekiq.rb
+++ b/lib/bugsnag/integrations/sidekiq.rb
@@ -2,6 +2,11 @@
 
 module Bugsnag
   class Sidekiq
+
+    FRAMEWORK_ATTRIBUTES = {
+      :framework => "Sidekiq"
+    }
+
     def initialize
       Bugsnag.configuration.internal_middleware.use(Bugsnag::Middleware::Sidekiq)
       Bugsnag.configuration.app_type = "sidekiq"
@@ -18,6 +23,10 @@ def call(worker, msg, queue)
         raise ex if [Interrupt, SystemExit, SignalException].include? ex.class
         Bugsnag.notify(ex, true) do |report|
           report.severity = "error"
+          report.severity_reason = {
+            :type => Bugsnag::Report::UNHANDLED_EXCEPTION_MIDDLEWARE,
+            :attributes => FRAMEWORK_ATTRIBUTES
+          }
         end
         raise
       ensure
diff --git a/lib/bugsnag/middleware/classify_error.rb b/lib/bugsnag/middleware/classify_error.rb
new file mode 100644
index 000000000..0867a6432
--- /dev/null
+++ b/lib/bugsnag/middleware/classify_error.rb
@@ -0,0 +1,48 @@
+module Bugsnag::Middleware
+  class ClassifyError
+    INFO_CLASSES = [
+        "AbstractController::ActionNotFound",
+        "ActionController::InvalidAuthenticityToken",
+        "ActionController::ParameterMissing",
+        "ActionController::UnknownAction",
+        "ActionController::UnknownFormat",
+        "ActionController::UnknownHttpMethod",
+        "ActiveRecord::RecordNotFound",
+        "CGI::Session::CookieStore::TamperedWithCookie",
+        "Mongoid::Errors::DocumentNotFound",
+        "SignalException",
+        "SystemExit"
+    ]
+
+    def initialize(bugsnag)
+      @bugsnag = bugsnag
+    end
+
+    def call(report)
+      report.raw_exceptions.each do |ex|
+
+        ancestor_chain = ex.class.ancestors.select {
+          |ancestor| ancestor.is_a?(Class) 
+        }.map {
+          |ancestor| ancestor.to_s
+        }
+
+        INFO_CLASSES.each do |info_class|
+          if ancestor_chain.include?(info_class) 
+            report.severity_reason = {
+              :type => Bugsnag::Report::ERROR_CLASS,
+              :attributes => {
+                :errorClass => info_class
+              }
+            }
+            report.severity = 'info'
+            break
+          end
+        end
+      end
+
+      @bugsnag.call(report)
+    end
+  end
+end
+  
\ No newline at end of file
diff --git a/lib/bugsnag/report.rb b/lib/bugsnag/report.rb
index 5f3c289eb..3ed2d78e0 100644
--- a/lib/bugsnag/report.rb
+++ b/lib/bugsnag/report.rb
@@ -8,6 +8,13 @@ class Report
     NOTIFIER_VERSION = Bugsnag::VERSION
     NOTIFIER_URL = "http://www.bugsnag.com"
 
+    UNHANDLED_EXCEPTION = "unhandledException"
+    UNHANDLED_EXCEPTION_MIDDLEWARE = "unhandledExceptionMiddleware"
+    ERROR_CLASS = "errorClass"
+    HANDLED_EXCEPTION = "handledException"
+    USER_SPECIFIED_SEVERITY = "userSpecifiedSeverity"
+    USER_CALLBACK_SET_SEVERITY = "userCallbackSetSeverity"
+
     MAX_EXCEPTIONS_TO_UNWRAP = 5
 
     CURRENT_PAYLOAD_VERSION = "2"
@@ -25,10 +32,12 @@ class Report
     attr_accessor :raw_exceptions
     attr_accessor :release_stage
     attr_accessor :severity
+    attr_accessor :severity_reason
     attr_accessor :user
 
-    def initialize(exception, passed_configuration)
+    def initialize(exception, passed_configuration, auto_notify=false)
       @should_ignore = false
+      @unhandled = auto_notify
 
       self.configuration = passed_configuration
 
@@ -42,7 +51,8 @@ def initialize(exception, passed_configuration)
       self.hostname = configuration.hostname
       self.meta_data = {}
       self.release_stage = configuration.release_stage
-      self.severity = "warning"
+      self.severity = auto_notify ? "error" : "warning"
+      self.severity_reason = auto_notify ? {:type => UNHANDLED_EXCEPTION} : {:type => HANDLED_EXCEPTION}
       self.user = {}
     end
 
@@ -84,6 +94,8 @@ def as_json
         groupingHash: grouping_hash,
         payloadVersion: CURRENT_PAYLOAD_VERSION,
         severity: severity,
+        severityReason: severity_reason,
+        unhandled: @unhandled,
         user: user
       }
 
diff --git a/lib/bugsnag/tasks/bugsnag.rake b/lib/bugsnag/tasks/bugsnag.rake
index 25618bef2..be214b3da 100644
--- a/lib/bugsnag/tasks/bugsnag.rake
+++ b/lib/bugsnag/tasks/bugsnag.rake
@@ -6,7 +6,9 @@ namespace :bugsnag do
     begin
       raise RuntimeError.new("Bugsnag test exception")
     rescue => e
-      Bugsnag.notify(e, {:context => "rake#test_exception"})
+      Bugsnag.notify(e) do |report|
+        report.context = "rake#test_exception"
+      end
     end
   end
 end
diff --git a/spec/middleware_spec.rb b/spec/middleware_spec.rb
index 24b9f8f91..267669e4f 100644
--- a/spec/middleware_spec.rb
+++ b/spec/middleware_spec.rb
@@ -178,4 +178,43 @@ def call(report)
     }
   end
 
+  it "doesn't allow handledState properties to be changed in middleware" do
+    HandledStateChanger = Class.new do
+      def initialize(bugsnag)
+        @bugsnag = bugsnag
+      end
+
+      def call(report)
+        report.severity_reason = {
+          :test => "test"
+        }
+        @bugsnag.call(report)
+      end
+    end
+
+    Bugsnag.configure do |c|
+      c.middleware.use HandledStateChanger
+    end
+
+    Bugsnag.notify(BugsnagTestException.new("It crashed"), true) do |report|
+      report.severity_reason = {
+        :type => "middleware_handler",
+        :attributes => {
+          :name => "middleware_test"
+        }
+      }
+    end
+
+    expect(Bugsnag).to have_sent_notification{ |payload|
+      event = get_event_from_payload(payload)
+      expect(event["unhandled"]).to be true
+      expect(event["severityReason"]).to eq({
+        "type" => "middleware_handler",
+        "attributes" => {
+          "name" => "middleware_test"
+        }
+      })
+    }
+  end
+
 end
diff --git a/spec/report_spec.rb b/spec/report_spec.rb
index 7a0947bc8..dbdae3b52 100644
--- a/spec/report_spec.rb
+++ b/spec/report_spec.rb
@@ -387,18 +387,6 @@ def gloops
     }
   end
 
-  it "autonotifies errors" do
-    Bugsnag.notify(BugsnagTestException.new("It crashed"), true) do |report|
-      report.severity = "error"
-    end
-
-    expect(Bugsnag).to have_sent_notification{ |payload|
-      event = get_event_from_payload(payload)
-      expect(event["severity"]).to eq("error")
-    }
-  end
-
-
   it "accepts a context in overrides" do
     Bugsnag.notify(BugsnagTestException.new("It crashed")) do |report|
       report.context = 'test_context'
@@ -421,7 +409,7 @@ def gloops
     }
   end
 
-  it "does not send a notification if auto_notify is false" do
+  it "does not send an automatic notification if auto_notify is false" do
     Bugsnag.configure do |config|
       config.auto_notify = false
     end
@@ -888,6 +876,57 @@ def gloops
     }
   end
 
+  it 'should use defaults when notify is called' do
+    Bugsnag.notify(BugsnagTestException.new("It crashed"))
+    
+    expect(Bugsnag).to have_sent_notification{ |payload|
+      event = payload["events"][0]
+      expect(event["unhandled"]).to be false
+      expect(event["severityReason"]).to eq({"type" => "handledException"})
+    }
+  end
+
+  it 'should attach severity reason through a block when auto_notify is true' do
+    Bugsnag.notify(BugsnagTestException.new("It crashed"), true) do |report|
+      report.severity_reason = {
+        :type => "middleware_handler",
+        :attributes => {
+          :name => "middleware_test"
+        }
+      }
+    end
+
+    expect(Bugsnag).to have_sent_notification{ |payload|
+      event = payload["events"][0]
+      expect(event["severityReason"]).to eq(
+        {
+          "type" => "middleware_handler",
+          "attributes" => {
+            "name" => "middleware_test"
+          }
+        }
+      )
+      expect(event["unhandled"]).to be true
+    }
+  end
+
+  it 'should not attach severity reason from callback when auto_notify is false' do
+    Bugsnag.notify(BugsnagTestException.new("It crashed")) do |report|
+      report.severity_reason = {
+        :type => "middleware_handler",
+        :attributes => {
+          :name => "middleware_test"
+        }
+      }
+    end
+
+    expect(Bugsnag).to have_sent_notification{ |payload|
+      event = payload["events"][0]
+      expect(event["unhandled"]).to be false
+      expect(event["severityReason"]).to eq({"type" => "handledException"})
+    }
+  end
+
   if defined?(JRUBY_VERSION)
 
     it "should work with java.lang.Throwables" do