diff --git a/lib/fluent/plugin/out_forward.rb b/lib/fluent/plugin/out_forward.rb
index a8ee808fbc..8824e3d391 100644
--- a/lib/fluent/plugin/out_forward.rb
+++ b/lib/fluent/plugin/out_forward.rb
@@ -29,6 +29,8 @@ class ACKTimeoutError < Error; end
 
     Fluent::Plugin.register_output('forward', self)
 
+    helpers :compat_parameters
+
     LISTEN_PORT = 24224
 
     desc 'The timeout time when sending event logs.'
@@ -111,6 +113,8 @@ def initialize
     end
 
     def configure(conf)
+      compat_parameters_convert(conf, :buffer, default_chunk_key: 'tag')
+
       super
 
       unless @chunk_key_tag
diff --git a/test/plugin/test_out_forward.rb b/test/plugin/test_out_forward.rb
index ea7cb26ae8..8416aa5c9d 100644
--- a/test/plugin/test_out_forward.rb
+++ b/test/plugin/test_out_forward.rb
@@ -78,6 +78,24 @@ def test_configure
     assert_equal TARGET_PORT, node.port
   end
 
+  def test_configure_traditional
+    d = create_driver(<<EOL)
+      self_hostname localhost
+      <server>
+        name test
+        host #{TARGET_HOST}
+        port #{TARGET_PORT}
+      </server>
+      buffer_chunk_limit 10m
+EOL
+    instance = d.instance
+    assert instance.chunk_key_tag
+    assert !instance.chunk_key_time
+    assert_equal [], instance.chunk_keys
+    assert{ instance.buffer.is_a?(Fluent::Plugin::MemoryBuffer) }
+    assert_equal( 10*1024*1024, instance.buffer.chunk_limit_size )
+  end
+
   def test_configure_udp_heartbeat
     d = create_driver(CONFIG + "\nheartbeat_type udp")
     assert_equal :udp, d.instance.heartbeat_type