diff -r f8f63e944375 sys/src/cmd/upas/common/common.h
--- a/sys/src/cmd/upas/common/common.h	Fri Jul 17 16:53:20 2020 +0200
+++ b/sys/src/cmd/upas/common/common.h	Sat Jul 18 23:30:20 2020 -0700
@@ -52,9 +52,6 @@
 void	mailfmtinstall(void);	/* 'U' = 2047fmt */
 #pragma varargck	type	"U"	char*
 
-/* totm.c */
-int	fromtotm(char*, Tm*);
-
 /* a pipe between parent and child*/
 typedef struct{
 	Biobuf	bb;
diff -r f8f63e944375 sys/src/cmd/upas/common/folder.c
--- a/sys/src/cmd/upas/common/folder.c	Fri Jul 17 16:53:20 2020 +0200
+++ b/sys/src/cmd/upas/common/folder.c	Sat Jul 18 23:30:20 2020 -0700
@@ -1,5 +1,7 @@
 #include "common.h"
 
+#define Ctimefmt "W MMM _D hh:mm:ss ZZZ YYYY"
+
 enum{
 	Mbox	= 1,
 	Mdir,
@@ -185,7 +187,7 @@
 appendfolder(Biobuf *b, char *addr, int fd)
 {
 	char *s;
-	int r;
+	int r, n;
 	Biobuf bin;
 	Folder *f;
 	Tm tm;
@@ -194,9 +196,10 @@
 	Bseek(f->out, 0, 2);
 	Binit(&bin, fd, OREAD);
 	s = Brdstr(&bin, '\n', 0);
-	if(!s || strncmp(s, "From ", 5))
+	n = strlen(s);
+	if(!s || strncmp(s, "From ", 5) != 0)
 		Bprint(f->out, "From %s %.28s\n", addr, ctime(f->t));
-	else if(fromtotm(s, &tm) >= 0)
+	else if(n > 5 && tmparse(&tm, Ctimefmt, s + 5, nil, nil) != nil)
 		f->t = tm2sec(&tm);
 	if(s)
 		Bwrite(f->out, s, strlen(s));
diff -r f8f63e944375 sys/src/cmd/upas/common/mkfile
--- a/sys/src/cmd/upas/common/mkfile	Fri Jul 17 16:53:20 2020 +0200
+++ b/sys/src/cmd/upas/common/mkfile	Sat Jul 18 23:30:20 2020 -0700
@@ -10,7 +10,6 @@
 	fmt.$O\
 	libsys.$O\
 	process.$O\
-	totm.$O\
 
 HFILES=common.h\
 	sys.h\
diff -r f8f63e944375 sys/src/cmd/upas/common/totm.c
--- a/sys/src/cmd/upas/common/totm.c	Fri Jul 17 16:53:20 2020 +0200
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,36 +0,0 @@
-#include <common.h>
-
-static char mtab[] = "JanFebMarAprMayJunJulAugSepOctNovDec";
-
-int
-ctimetotm(char *s, Tm *tm)
-{
-	char buf[32];
-
-	if(strlen(s) < 28)
-		return -1;
-	snprint(buf, sizeof buf, "%s", s);
-	memset(tm, 0, sizeof *tm);
-	buf[7] = 0;
-	tm->mon = (strstr(mtab, buf+4) - mtab)/3;
-	tm->mday = atoi(buf+8);
-	tm->hour = atoi(buf+11);
-	tm->min = atoi(buf+14);
-	tm->sec = atoi(buf+17);
-	tm->zone[0] = buf[20];
-	tm->zone[1] = buf[21];
-	tm->zone[2] = buf[22];
-	tm->year = atoi(buf+24) - 1900;
-	return 0;
-}
-
-int
-fromtotm(char *s, Tm *tm)
-{
-	char buf[256], *f[3];
-
-	snprint(buf, sizeof buf, "%s", s);
-	if(getfields(buf, f, nelem(f), 0, " ") != 3)
-		return -1;
-	return ctimetotm(f[2], tm);
-}