diff --git a/check.t b/check.t
index 21b9873..120fb95 100644
--- a/check.t
+++ b/check.t
@@ -1,4 +1,4 @@
-# $MirOS: src/bin/mksh/check.t,v 1.662 2014/10/10 22:10:19 tg Exp $
+# $MirOS: src/bin/mksh/check.t,v 1.663 2014/10/12 19:54:58 tg Exp $
 # OpenBSD src/regress/bin/ksh updated: 2013/12/02 20:39:44
 #-
 # Copyright © 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
@@ -27,7 +27,7 @@
 # http://www.freebsd.org/cgi/cvsweb.cgi/src/tools/regression/bin/test/regress.sh?rev=HEAD
 
 expected-stdout:
-	@(#)MIRBSD KSH R50 2014/10/07
+	@(#)MIRBSD KSH R50 2014/10/12
 description:
 	Check version of shell.
 stdin:
@@ -36,7 +36,7 @@ name: KSH_VERSION
 category: shell:legacy-no
 ---
 expected-stdout:
-	@(#)LEGACY KSH R50 2014/10/07
+	@(#)LEGACY KSH R50 2014/10/12
 description:
 	Check version of legacy shell.
 stdin:
@@ -2389,6 +2389,14 @@ stdin:
 	vf=<<<$'=f $x \x40='
 	# now check
 	print -r -- "| va={$va} vb={$vb} vc={$vc} vd={$vd} ve={$ve} vf={$vf} |"
+	# check append
+	v=<<-EOF
+		vapp1
+	EOF
+	v+=<<-EOF
+		vapp2
+	EOF
+	print -r -- "| ${v//$'\n'/^} |"
 expected-stdout:
 	function foo {
 		vc=<<-EOF
@@ -2404,6 +2412,7 @@ expected-stdout:
 	} ve={=e $x \x40=
 	} vf={=f $x @=
 	} |
+	| vapp1^vapp2^ |
 ---
 name: heredoc-11
 description:
@@ -2433,6 +2442,14 @@ stdin:
 	eval "$fnd"
 	foo
 	print -r -- "| va={$va} vb={$vb} vc={$vc} vd={$vd} |"
+	# check append
+	v=<<-
+		vapp1
+	<<
+	v+=<<-''
+		vapp2
+	
+	print -r -- "| ${v//$'\n'/^} |"
 expected-stdout:
 	function foo {
 		vc=<<-
@@ -2450,6 +2467,7 @@ expected-stdout:
 	} vc={=c u \x40=
 	} vd={=d $x \x40=
 	} |
+	| vapp1^vapp2^ |
 ---
 name: heredoc-comsub-1
 description:
diff --git a/exec.c b/exec.c
index b60511d..fa1c38a 100644
--- a/exec.c
+++ b/exec.c
@@ -23,7 +23,7 @@
 
 #include "sh.h"
 
-__RCSID("$MirOS: src/bin/mksh/exec.c,v 1.133 2014/10/03 17:32:11 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/exec.c,v 1.134 2014/10/12 19:55:00 tg Exp $");
 
 #ifndef MKSH_DEFAULT_EXECSHELL
 #define MKSH_DEFAULT_EXECSHELL	"/bin/sh"
@@ -94,11 +94,14 @@ execute(struct op * volatile t,
 		    /* the variable assignment begins with a valid varname */
 		    (ccp = skip_wdvarname(t->vars[0], true)) != t->vars[0] &&
 		    /* and has no right-hand side (i.e. "varname=") */
-		    ccp[0] == CHAR && ccp[1] == '=' && ccp[2] == EOS &&
+		    ccp[0] == CHAR && ((ccp[1] == '=' && ccp[2] == EOS) ||
+		    /* or "varname+=" */ (ccp[1] == '+' && ccp[2] == CHAR &&
+		    ccp[3] == '=' && ccp[4] == EOS)) &&
 		    /* plus we can have a here document content */
 		    herein(t->ioact[0], &cp) == 0 && cp && *cp) {
 			char *sp = cp, *dp;
-			size_t n = ccp - t->vars[0] + 2, z;
+			size_t n = ccp - t->vars[0] + (ccp[1] == '+' ? 4 : 2);
+			size_t z;
 
 			/* drop redirection (will be garbage collected) */
 			t->ioact = NULL;
diff --git a/sh.h b/sh.h
index b3d1c0b..b46cc46 100644
--- a/sh.h
+++ b/sh.h
@@ -169,9 +169,9 @@
 #endif
 
 #ifdef EXTERN
-__RCSID("$MirOS: src/bin/mksh/sh.h,v 1.697 2014/10/07 15:22:17 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/sh.h,v 1.698 2014/10/12 19:55:01 tg Exp $");
 #endif
-#define MKSH_VERSION "R50 2014/10/07"
+#define MKSH_VERSION "R50 2014/10/12"
 
 /* arithmetic types: C implementation */
 #if !HAVE_CAN_INTTYPES