diff --git a/Ethernet/Socket_APIs.chm b/Ethernet/Socket_APIs.chm
deleted file mode 100644
index 1d10d65..0000000
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diff --git a/Ethernet/Socket_APIs_V3.0.3.chm b/Ethernet/Socket_APIs_V3.0.3.chm
new file mode 100644
index 0000000..5ed4b92
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diff --git a/Ethernet/Socket_APIs_V3.0.chm b/Ethernet/Socket_APIs_V3.0.chm
deleted file mode 100644
index 58570f2..0000000
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diff --git a/Ethernet/socket.c b/Ethernet/socket.c
index 79a6207..06b1f6a 100644
--- a/Ethernet/socket.c
+++ b/Ethernet/socket.c
@@ -197,7 +197,22 @@ int8_t socket(uint8_t sn, uint8_t protocol, uint16_t port, uint8_t flag)
 int8_t close(uint8_t sn)
 {
 	CHECK_SOCKNUM();
-	
+//A20160426 : Applied the erratum 1 of W5300
+#if   (_WIZCHIP_ == 5300) 
+   if( ((getSn_MR(s)& 0x0F) == Sn_MR_TCP) && (getSn_TX_FSR(s) != getSn_TxMAX(s)) ) 
+   { 
+      uint8 destip[4] = {0, 0, 0, 1};
+      // TODO
+      // You can wait for completing to sending data;
+      // wait about 1 second;
+      // if you have completed to send data, skip the code of erratum 1
+      // ex> wait_1s();
+      //     if (getSn_TX_FSR(s) == getSn_TxMAX(s)) continue;
+      // 
+      socket(s,Sn_MR_UDP,0x3000,0);
+      sendto(s,destip,1,destip,0x3000); // send the dummy data to an unknown destination(0.0.0.1).
+   };   
+#endif 
 	setSn_CR(sn,Sn_CR_CLOSE);
    /* wait to process the command... */
 	while( getSn_CR(sn) );
diff --git a/README.md b/README.md
index 365ac18..5c09e42 100644
--- a/README.md
+++ b/README.md
@@ -27,6 +27,8 @@ This driver provides the Berkeley Socket type APIs.
     - Define what Host I/F mode is used in **wizchip_conf.h**
 
 ## Revision History
+  * ioLibrary V3.0.2 Released : 26, April, 2016
+    * Applied the erratum #1 in close() of socket.c (Refer to A20160426)
   * ioLibrary V3.0.1 Released : 15, July, 2015
     * Bug fixed : In W5100, Fixed CS control problem in read/write buffer with SPI. Refer to M20150715.
   * ioLibrary V3.0 Released : 01, June, 2015