diff --git a/lib/mongo_mapper.rb b/lib/mongo_mapper.rb
old mode 100644
new mode 100755
index aa764aa91..94586dd12
--- a/lib/mongo_mapper.rb
+++ b/lib/mongo_mapper.rb
@@ -20,6 +20,7 @@ module MongoMapper
   autoload :Plugins,                'mongo_mapper/plugins'
   autoload :Translation,            'mongo_mapper/translation'
   autoload :Version,                'mongo_mapper/version'
+  autoload :Utils,                  'mongo_mapper/utils'
 
   module Middleware
     autoload :IdentityMap, 'mongo_mapper/middleware/identity_map'
diff --git a/lib/mongo_mapper/connection.rb b/lib/mongo_mapper/connection.rb
index a2d967288..a9576dfb3 100755
--- a/lib/mongo_mapper/connection.rb
+++ b/lib/mongo_mapper/connection.rb
@@ -10,7 +10,7 @@ module Connection
 
     # @api public
     def connection
-      @@connection ||= Mongo::Connection.new
+      @@connection ||= Mongo::MongoClient.new
     end
 
     # @api public
@@ -75,12 +75,12 @@ def connect(environment, options={})
 
       MongoMapper.connection = if env['hosts']
         if env['hosts'].first.is_a?(String)
-          Mongo::ReplSetConnection.new( env['hosts'], options )
+          Mongo::MongoReplicaSetClient.new( env['hosts'], options )
         else
-          Mongo::ReplSetConnection.new( *env['hosts'].push(options) )
+          Mongo::MongoReplicaSetClient.new( *env['hosts'].push(options) )
         end
       else
-        Mongo::Connection.new(env['host'], env['port'], options)
+        Mongo::MongoClient.new(env['host'], env['port'], options)
       end
 
       MongoMapper.database = env['database']
diff --git a/lib/mongo_mapper/plugins/modifiers.rb b/lib/mongo_mapper/plugins/modifiers.rb
old mode 100644
new mode 100755
index 55080c3c8..a83b69e15
--- a/lib/mongo_mapper/plugins/modifiers.rb
+++ b/lib/mongo_mapper/plugins/modifiers.rb
@@ -79,6 +79,7 @@ def criteria_and_keys_from_args(args)
               criteria = args[0]
               updates  = args[1]
               options  = args[2]
+              upgrade_legacy_safe_usage(options)
             else
               criteria, (updates, options) = args.partition { |a| !a.is_a?(Hash) }
               criteria = { :id => criteria }
@@ -86,6 +87,13 @@ def criteria_and_keys_from_args(args)
 
             [criteria_hash(criteria).to_hash, updates, options]
           end
+
+          def upgrade_legacy_safe_usage(options)
+            if options and options.key?(:safe)
+              options.delete :safe
+              options.merge! Utils.get_safe_options(options)
+            end
+          end
       end
 
       def unset(*args)
diff --git a/lib/mongo_mapper/plugins/querying.rb b/lib/mongo_mapper/plugins/querying.rb
old mode 100644
new mode 100755
index 5fdacbeff..e70e39efe
--- a/lib/mongo_mapper/plugins/querying.rb
+++ b/lib/mongo_mapper/plugins/querying.rb
@@ -158,7 +158,7 @@ def update(options={})
 
         def save_to_collection(options={})
           @_new = false
-          collection.save(to_mongo, :safe => options[:safe])
+          collection.save(to_mongo, Utils.get_safe_options(options))
         end
     end
   end
diff --git a/lib/mongo_mapper/utils.rb b/lib/mongo_mapper/utils.rb
new file mode 100755
index 000000000..48bfcc6f4
--- /dev/null
+++ b/lib/mongo_mapper/utils.rb
@@ -0,0 +1,11 @@
+module MongoMapper
+  module Utils
+    def self.get_safe_options(options)
+      safe = options[:safe]
+      safe = {:w => 1} if safe == true or safe.nil?
+      safe = {:w => 0} if safe == false
+      safe = {:w => safe} if safe.is_a? Fixnum
+      safe
+    end
+  end
+end
\ No newline at end of file
diff --git a/test/functional/test_modifiers.rb b/test/functional/test_modifiers.rb
old mode 100644
new mode 100755
index f9d8c6bb3..881055fb5
--- a/test/functional/test_modifiers.rb
+++ b/test/functional/test_modifiers.rb
@@ -76,9 +76,9 @@ def assert_keys_removed(page, *keys)
           Mongo::Collection.any_instance.expects(:update).with(
             {:title => "Better Be Safe than Sorry"},
             {'$unset' => {:tags => 1}},
-            {:safe => true, :multi => true}
+            {:w => 1, :multi => true}
           )
-          @page_class.unset({:title => "Better Be Safe than Sorry"}, :tags, {:safe => true})
+          @page_class.unset({:title => "Better Be Safe than Sorry"}, :tags, {:w => 1})
         end
 
         should "be able to pass both safe and upsert options" do
@@ -215,7 +215,7 @@ def assert_keys_removed(page, *keys)
           Mongo::Collection.any_instance.expects(:update).with(
             {:title => "Better Be Safe than Sorry"},
             {'$set' => {:title => "I like safety."}},
-            {:safe => true, :multi => true}
+            {:w => 1, :multi => true}
           )
           @page_class.set({:title => "Better Be Safe than Sorry"}, {:title => "I like safety."}, {:safe => true})
         end
diff --git a/test/functional/test_safe.rb b/test/functional/test_safe.rb
old mode 100644
new mode 100755
index d49f7b89e..228b081e3
--- a/test/functional/test_safe.rb
+++ b/test/functional/test_safe.rb
@@ -46,9 +46,9 @@ class SafeTest < Test::Unit::TestCase
       end
 
       context "using safe setting from class" do
-        should "pass :safe => true option to save" do
+        should "pass :w => 1 option to save" do
           instance = @klass.new(:email => 'john@doe.com')
-          Mongo::Collection.any_instance.expects(:save).once.with({'_id' => instance.id, 'email' => 'john@doe.com'}, {:safe => true})
+          Mongo::Collection.any_instance.expects(:save).once.with({'_id' => instance.id, 'email' => 'john@doe.com'}, {:w => 1})
           instance.save!
         end
 
@@ -103,7 +103,7 @@ class SafeTest < Test::Unit::TestCase
       context "using safe setting from class" do
         should "pass :safe => options_hash to save" do
           instance = @klass.new(:email => 'john@doe.com')
-          Mongo::Collection.any_instance.expects(:save).once.with({'_id' => instance.id, 'email' => 'john@doe.com'}, {:safe => {:j => true}})
+          Mongo::Collection.any_instance.expects(:save).once.with({'_id' => instance.id, 'email' => 'john@doe.com'}, {:j => true})
           instance.save!
         end