diff --git a/lib/bugsnag/configuration.rb b/lib/bugsnag/configuration.rb
index 2a1a79648..f41b6c4fc 100644
--- a/lib/bugsnag/configuration.rb
+++ b/lib/bugsnag/configuration.rb
@@ -29,8 +29,6 @@ class Configuration
     attr_accessor :delivery_method
     attr_accessor :ignore_classes
 
-    LOG_PREFIX = "** [Bugsnag] "
-
     THREAD_LOCAL_NAME = "bugsnag_req_data"
 
     DEFAULT_PARAMS_FILTERS = [
@@ -62,6 +60,9 @@ def initialize
       # Set up logging
       self.logger = Logger.new(STDOUT)
       self.logger.level = Logger::INFO
+      self.logger.formatter = proc do |severity, datetime, progname, msg|
+        "** [Bugsnag] #{datetime}: #{msg}\n"
+      end
 
       # Configure the bugsnag middleware stack
       self.internal_middleware = Bugsnag::MiddlewareStack.new
diff --git a/lib/bugsnag/middleware/exception_meta_data.rb b/lib/bugsnag/middleware/exception_meta_data.rb
index 709eb826d..34f44de92 100644
--- a/lib/bugsnag/middleware/exception_meta_data.rb
+++ b/lib/bugsnag/middleware/exception_meta_data.rb
@@ -14,6 +14,14 @@ def call(report)
           if exception.bugsnag_context.is_a?(String)
             report.context = exception.bugsnag_context
           end
+          if exception.bugsnag_grouping_hash.is_a?(String)
+            report.grouping_hash = exception.bugsnag_grouping_hash
+          end
+          if exception.respond_to?(:bugsnag_meta_data) && exception.bugsnag_meta_data
+            exception.bugsnag_meta_data.each do |key, value|
+              report.add_to_tab key, value
+            end
+          end
         end
       end
 
diff --git a/lib/bugsnag/report.rb b/lib/bugsnag/report.rb
index bdef28dc8..7b3553f75 100644
--- a/lib/bugsnag/report.rb
+++ b/lib/bugsnag/report.rb
@@ -22,13 +22,12 @@ class Report
     attr_accessor :meta_data
     attr_accessor :severity
 
-    def initialize(exception, configuration, request_data = nil)
-      configuration = configuration
-      @request_data = request_data
+    def initialize(exception, configuration)
       @user = {}
       @should_ignore = false
 
       self.api_key = configuration.api_key
+      self.configuration = configuration
       self.delivery_method = configuration.delivery_method
       self.meta_data = {}
       self.severity = "warning"
@@ -67,12 +66,6 @@ def initialize(exception, configuration, request_data = nil)
       end
     end
 
-    # Add a single value as custom data, to this notification
-    def add_custom_data(name, value)
-      @meta_data[:custom] ||= {}
-      @meta_data[:custom][name.to_sym] = value
-    end
-
     # Add a new tab to this notification
     def add_tab(name, value)
       return if name.nil?
@@ -98,15 +91,6 @@ def user=(user = {})
       @user.merge!(user).delete_if{|k,v| v == nil}
     end
 
-    # Deliver this notification to bugsnag.com Also runs through the middleware as required.
-    def deliver
-      # Check we have at least an api_key
-      
-
-      # make meta_data available to public middleware
-      @meta_data = generate_meta_data(@exceptions, @overrides)
-    end
-
     # Build an exception payload
     def as_json
       # Build the payload's exception event
@@ -150,7 +134,7 @@ def ignore?
     end
 
     def request_data
-      @request_data || Bugsnag.configuration.request_data
+      @configuration.request_data
     end
 
     def exceptions
@@ -181,44 +165,6 @@ def ignore_user_agent?
       end
     end
 
-    # Generate the meta data from both the request configuration, the overrides and the exceptions for this notification
-    def generate_meta_data(exceptions, overrides)
-      # Copy the request meta data so we dont edit it by mistake
-      meta_data = @meta_data.dup
-
-      exceptions.each do |exception|
-        if exception.respond_to?(:bugsnag_meta_data) && exception.bugsnag_meta_data
-          exception.bugsnag_meta_data.each do |key, value|
-            add_to_meta_data key, value, meta_data
-          end
-        end
-      end
-
-      overrides.each do |key, value|
-        add_to_meta_data key, value, meta_data
-      end
-
-      meta_data
-    end
-
-    def add_to_meta_data(key, value, meta_data)
-      # If its a hash, its a tab so we can just add it providing its not reserved
-      if value.is_a? Hash
-        key = key.to_sym
-
-        if meta_data[key]
-          # If its a clash, merge with the existing data
-          meta_data[key].merge! value
-        else
-          # Add it as is if its not special
-          meta_data[key] = value
-        end
-      else
-        meta_data[:custom] ||= {}
-        meta_data[:custom][key] = value
-      end
-    end
-
     def exception_list
       @exceptions.map do |exception|
         {
diff --git a/spec/notification_spec.rb b/spec/notification_spec.rb
index 3cc964a83..5b50ca18e 100644
--- a/spec/notification_spec.rb
+++ b/spec/notification_spec.rb
@@ -223,6 +223,18 @@ def gloops
     }
   end
 
+  it "accepts grouping_hash from an exception that mixes in Bugsnag::MetaData" do
+    exception = BugsnagTestExceptionWithMetaData.new("It crashed")
+    exception.bugsnag_grouping_hash = "exception_hash"
+
+    Bugsnag.notify(exception)
+
+    expect(Bugsnag).to have_sent_notification{ |payload|
+      event = get_event_from_payload(payload)
+      expect(event["groupingHash"]).to eq("exception_hash")
+    }
+  end
+
   it "accept contexts from an exception that mixes in Bugsnag::MetaData, but override using the overrides" do
 
     exception = BugsnagTestExceptionWithMetaData.new("It crashed")