diff --git a/mysql-test/r/rpl_switch_stm_row_mixed.result b/mysql-test/r/rpl_switch_stm_row_mixed.result
index c319005b2a4..cb31301bcd3 100644
--- a/mysql-test/r/rpl_switch_stm_row_mixed.result
+++ b/mysql-test/r/rpl_switch_stm_row_mixed.result
@@ -7,6 +7,8 @@ start slave;
 drop database if exists mysqltest1;
 create database mysqltest1;
 use mysqltest1;
+set session binlog_format=row;
+set global binlog_format=row;
 show global variables like "binlog_format%";
 Variable_name	Value
 binlog_format	ROW
@@ -334,6 +336,26 @@ count(*)
 select count(*) from t5;
 count(*)
 58
+SET SESSION BINLOG_FORMAT=STATEMENT;
+CREATE TABLE t11 (song VARCHAR(255));
+LOCK TABLES t11 WRITE;
+SET SESSION BINLOG_FORMAT=ROW;
+INSERT INTO t11 VALUES('Several Species of Small Furry Animals Gathered Together in a Cave and Grooving With a Pict');
+SET SESSION BINLOG_FORMAT=STATEMENT;
+INSERT INTO t11 VALUES('Careful With That Axe, Eugene');
+UNLOCK TABLES;
+SELECT * FROM t11;
+song	Several Species of Small Furry Animals Gathered Together in a Cave and Grooving With a Pict
+song	Careful With That Axe, Eugene
+USE mysqltest1;
+SELECT * FROM t11;
+song	Several Species of Small Furry Animals Gathered Together in a Cave and Grooving With a Pict
+song	Careful With That Axe, Eugene
+SET SESSION BINLOG_FORMAT=MIXED;
+CREATE TABLE t12 (data LONG);
+LOCK TABLES t12 WRITE;
+INSERT INTO t12 VALUES(UUID());
+UNLOCK TABLES;
 select count(*) from t11;
 count(*)
 8
@@ -463,6 +485,13 @@ master-bin.000001	#	Table_map	1	#	table_id: # (mysqltest1.t1)
 master-bin.000001	#	Write_rows	1	#	table_id: # flags: STMT_END_F
 master-bin.000001	#	Table_map	1	#	table_id: # (mysqltest1.t1)
 master-bin.000001	#	Write_rows	1	#	table_id: # flags: STMT_END_F
+master-bin.000001	#	Query	1	#	use `mysqltest1`; CREATE TABLE t11 (song VARCHAR(255))
+master-bin.000001	#	Table_map	1	#	table_id: # (mysqltest1.t11)
+master-bin.000001	#	Write_rows	1	#	table_id: # flags: STMT_END_F
+master-bin.000001	#	Query	1	#	use `mysqltest1`; INSERT INTO t11 VALUES('Careful With That Axe, Eugene')
+master-bin.000001	#	Query	1	#	use `mysqltest1`; CREATE TABLE t12 (data LONG)
+master-bin.000001	#	Table_map	1	#	table_id: # (mysqltest1.t12)
+master-bin.000001	#	Write_rows	1	#	table_id: # flags: STMT_END_F
 master-bin.000001	#	Table_map	1	#	table_id: # (mysqltest1.t1)
 master-bin.000001	#	Write_rows	1	#	table_id: # flags: STMT_END_F
 master-bin.000001	#	Table_map	1	#	table_id: # (mysqltest1.t1)
diff --git a/mysql-test/t/rpl_switch_stm_row_mixed.test b/mysql-test/t/rpl_switch_stm_row_mixed.test
index 6d282069ba1..4cef32161ed 100644
--- a/mysql-test/t/rpl_switch_stm_row_mixed.test
+++ b/mysql-test/t/rpl_switch_stm_row_mixed.test
@@ -1,4 +1,4 @@
--- source include/have_binlog_format_row.inc
+-- source include/have_row_based.inc
 -- source include/master-slave.inc
 
 connection master;
@@ -8,6 +8,9 @@ create database mysqltest1;
 --enable_warnings
 use mysqltest1;
 
+set session binlog_format=row;
+set global binlog_format=row;
+
 show global variables like "binlog_format%";
 show session variables like "binlog_format%";
 select @@global.binlog_format, @@session.binlog_format;
@@ -461,7 +464,38 @@ if ($you_want_to_test_UDF)
   select count(*) from t9;
 }
 
+#
+# Bug#20863 If binlog format is changed between update and unlock of
+#           tables, wrong binlog
+#
+
+connection master;
+SET SESSION BINLOG_FORMAT=STATEMENT;
+CREATE TABLE t11 (song VARCHAR(255));
+LOCK TABLES t11 WRITE;
+SET SESSION BINLOG_FORMAT=ROW;
+INSERT INTO t11 VALUES('Several Species of Small Furry Animals Gathered Together in a Cave and Grooving With a Pict');
+SET SESSION BINLOG_FORMAT=STATEMENT;
+INSERT INTO t11 VALUES('Careful With That Axe, Eugene');
+UNLOCK TABLES;
+
+--query_vertical SELECT * FROM t11
 sync_slave_with_master;
+USE mysqltest1;
+--query_vertical SELECT * FROM t11
+
+connection master;
+SET SESSION BINLOG_FORMAT=MIXED;
+CREATE TABLE t12 (data LONG);
+LOCK TABLES t12 WRITE;
+INSERT INTO t12 VALUES(UUID());
+UNLOCK TABLES;
+
+--replace_column 2 # 5 #
+--replace_regex /table_id: [0-9]+/table_id: #/
+show binlog events from 102;
+sync_slave_with_master;
+
 # as we're using UUID we don't SELECT but use "diff" like in rpl_row_UUID
 --exec $MYSQL_DUMP --compact --order-by-primary --skip-extended-insert --no-create-info mysqltest1 > $MYSQLTEST_VARDIR/tmp/rpl_switch_stm_row_mixed_master.sql
 --exec $MYSQL_DUMP_SLAVE --compact --order-by-primary --skip-extended-insert --no-create-info mysqltest1 > $MYSQLTEST_VARDIR/tmp/rpl_switch_stm_row_mixed_slave.sql
diff --git a/sql/log.cc b/sql/log.cc
index dba4b65efd9..d796758fa92 100644
--- a/sql/log.cc
+++ b/sql/log.cc
@@ -3165,7 +3165,7 @@ int MYSQL_BIN_LOG::
   flush_and_set_pending_rows_event(THD *thd, Rows_log_event* event)
 {
   DBUG_ENTER("MYSQL_BIN_LOG::flush_and_set_pending_rows_event(event)");
-  DBUG_ASSERT(thd->current_stmt_binlog_row_based && mysql_bin_log.is_open());
+  DBUG_ASSERT(mysql_bin_log.is_open());
   DBUG_PRINT("enter", ("event=%p", event));
 
   int error= 0;
diff --git a/sql/sql_class.cc b/sql/sql_class.cc
index c1a3b76ce55..df87bf07269 100644
--- a/sql/sql_class.cc
+++ b/sql/sql_class.cc
@@ -2652,7 +2652,12 @@ int THD::binlog_delete_row(TABLE* table, bool is_trans,
 int THD::binlog_flush_pending_rows_event(bool stmt_end)
 {
   DBUG_ENTER("THD::binlog_flush_pending_rows_event");
-  if (!current_stmt_binlog_row_based || !mysql_bin_log.is_open())
+  /*
+    We shall flush the pending event even if we are not in row-based
+    mode: it might be the case that we left row-based mode before
+    flushing anything (e.g., if we have explicitly locked tables).
+   */
+  if (!mysql_bin_log.is_open())
     DBUG_RETURN(0);
 
   /*
@@ -2718,6 +2723,21 @@ int THD::binlog_query(THD::enum_binlog_query_type qtype,
   DBUG_PRINT("enter", ("qtype=%d, query='%s'", qtype, query));
   DBUG_ASSERT(query && mysql_bin_log.is_open());
 
+  /*
+    If we are not in prelocked mode, mysql_unlock_tables() will be
+    called after this binlog_query(), so we have to flush the pending
+    rows event with the STMT_END_F set to unlock all tables at the
+    slave side as well.
+
+    If we are in prelocked mode, the flushing will be done inside the
+    top-most close_thread_tables().
+  */
+#ifdef HAVE_ROW_BASED_REPLICATION
+  if (this->prelocked_mode == NON_PRELOCKED)
+    if (int error= binlog_flush_pending_rows_event(TRUE))
+      DBUG_RETURN(error);
+#endif /*HAVE_ROW_BASED_REPLICATION*/
+
   switch (qtype) {
   case THD::MYSQL_QUERY_TYPE:
     /*
@@ -2731,25 +2751,7 @@ int THD::binlog_query(THD::enum_binlog_query_type qtype,
   case THD::ROW_QUERY_TYPE:
 #ifdef HAVE_ROW_BASED_REPLICATION
     if (current_stmt_binlog_row_based)
-    {
-      /*
-        If thd->lock is set, then we are not inside a stored function.
-        In that case, mysql_unlock_tables() will be called after this
-        binlog_query(), so we have to flush the pending rows event
-        with the STMT_END_F set to unlock all tables at the slave side
-        as well.
-
-        We will not flush the pending event, if thd->lock is NULL.
-        This means that we are inside a stored function or trigger, so
-        the flushing will be done inside the top-most
-        close_thread_tables().
-       */
-#ifdef HAVE_ROW_BASED_REPLICATION
-      if (this->lock)
-        DBUG_RETURN(binlog_flush_pending_rows_event(TRUE));
-#endif /*HAVE_ROW_BASED_REPLICATION*/
       DBUG_RETURN(0);
-    }
 #endif
     /* Otherwise, we fall through */
   case THD::STMT_QUERY_TYPE: