diff --git a/input.c b/input.c
index 779b9013..f162b92f 100644
--- a/input.c
+++ b/input.c
@@ -1345,8 +1345,8 @@ input_csi_dispatch(struct input_ctx *ictx)
 	if (ictx->flags & INPUT_DISCARD)
 		return (0);
 
-	log_debug("%s: '%c' \"%s\" \"%s\"",
-	    __func__, ictx->ch, ictx->interm_buf, ictx->param_buf);
+	log_debug("%s: '%c' \"%s\" \"%s\"", __func__, ictx->ch,
+	    ictx->interm_buf, ictx->param_buf);
 
 	if (input_split(ictx) != 0)
 		return (0);
diff --git a/tmux.1 b/tmux.1
index c25440d4..1e325154 100644
--- a/tmux.1
+++ b/tmux.1
@@ -3690,6 +3690,8 @@ Supports the overline SGR attribute.
 Supports the DECFRA rectangle fill escape sequence.
 .It RGB
 Supports RGB colour with the SGR escape sequences.
+.It sixel
+Supports SIXEL graphics.
 .It strikethrough
 Supports the strikethrough SGR escape sequence.
 .It sync
@@ -5083,6 +5085,15 @@ would change
 .Ql abABab
 into
 .Ql bxBxbx .
+A different delimiter character may also be used, to avoid collisions with
+literal slashes in the pattern.
+For example,
+.Ql s|foo/|bar/|:
+will substitute
+.Ql foo/
+with
+.Ql bar/
+throughout.
 .Pp
 In addition, the last line of a shell command's output may be inserted using
 .Ql #() .
@@ -6485,6 +6496,8 @@ Set the opening sequence for the working directory notification.
 The sequence is terminated using the standard
 .Em fsl
 capability.
+.It Em \&Sxl
+Indicates that the terminal supports SIXEL.
 .It Em \&Sync
 Start (parameter is 1) or end (parameter is 2) a synchronized update.
 .It Em \&Tc
diff --git a/tmux.h b/tmux.h
index e88eac0f..751e8a99 100644
--- a/tmux.h
+++ b/tmux.h
@@ -544,6 +544,7 @@ enum tty_code_code {
 	TTYC_SMUL,
 	TTYC_SMULX,
 	TTYC_SMXX,
+	TTYC_SXL,
 	TTYC_SS,
 	TTYC_SWD,
 	TTYC_SYNC,
@@ -1350,6 +1351,7 @@ struct tty_term {
 #define TERM_DECFRA 0x8
 #define TERM_RGBCOLOURS 0x10
 #define TERM_VT100LIKE 0x20
+#define TERM_SIXEL 0x40
 	int		 flags;
 
 	LIST_ENTRY(tty_term) entry;
@@ -1406,9 +1408,10 @@ struct tty {
 #define TTY_OPENED 0x20
 #define TTY_OSC52QUERY 0x40
 #define TTY_BLOCK 0x80
-#define TTY_HAVEDA 0x100
+#define TTY_HAVEDA 0x100 /* Primary DA. */
 #define TTY_HAVEXDA 0x200
 #define TTY_SYNCING 0x400
+#define TTY_HAVEDA2 0x800 /* Seconday DA. */
 	int		 flags;
 
 	struct tty_term	*term;
diff --git a/tty-features.c b/tty-features.c
index 8ed61e9a..dca40fad 100644
--- a/tty-features.c
+++ b/tty-features.c
@@ -345,6 +345,17 @@ static const struct tty_feature tty_feature_ignorefkeys = {
 	0
 };
 
+/* Terminal has sixel capability. */
+static const char *const tty_feature_sixel_capabilities[] = {
+	"Sxl",
+	NULL
+};
+static const struct tty_feature tty_feature_sixel = {
+	"sixel",
+	tty_feature_sixel_capabilities,
+	TERM_SIXEL
+};
+
 /* Available terminal features. */
 static const struct tty_feature *const tty_features[] = {
 	&tty_feature_256,
@@ -362,6 +373,7 @@ static const struct tty_feature *const tty_features[] = {
 	&tty_feature_overline,
 	&tty_feature_rectfill,
 	&tty_feature_rgb,
+	&tty_feature_sixel,
 	&tty_feature_strikethrough,
 	&tty_feature_sync,
 	&tty_feature_title,
diff --git a/tty-keys.c b/tty-keys.c
index cb8efd49..6fe121f0 100644
--- a/tty-keys.c
+++ b/tty-keys.c
@@ -55,6 +55,8 @@ static int	tty_keys_clipboard(struct tty *, const char *, size_t,
 		    size_t *);
 static int	tty_keys_device_attributes(struct tty *, const char *, size_t,
 		    size_t *);
+static int	tty_keys_device_attributes2(struct tty *, const char *, size_t,
+		    size_t *);
 static int	tty_keys_extended_device_attributes(struct tty *, const char *,
 		    size_t, size_t *);
 
@@ -684,7 +686,7 @@ tty_keys_next(struct tty *tty)
 		goto partial_key;
 	}
 
-	/* Is this a device attributes response? */
+	/* Is this a primary device attributes response? */
 	switch (tty_keys_device_attributes(tty, buf, len, &size)) {
 	case 0:		/* yes */
 		key = KEYC_UNKNOWN;
@@ -695,6 +697,17 @@ tty_keys_next(struct tty *tty)
 		goto partial_key;
 	}
 
+	/* Is this a secondary device attributes response? */
+	switch (tty_keys_device_attributes2(tty, buf, len, &size)) {
+	case 0:		/* yes */
+		key = KEYC_UNKNOWN;
+		goto complete_key;
+	case -1:	/* no, or not valid */
+		break;
+	case 1:		/* partial */
+		goto partial_key;
+	}
+
 	/* Is this an extended device attributes response? */
 	switch (tty_keys_extended_device_attributes(tty, buf, len, &size)) {
 	case 0:		/* yes */
@@ -1235,7 +1248,7 @@ tty_keys_clipboard(struct tty *tty, const char *buf, size_t len, size_t *size)
 }
 
 /*
- * Handle secondary device attributes input. Returns 0 for success, -1 for
+ * Handle primary device attributes input. Returns 0 for success, -1 for
  * failure, 1 for partial.
  */
 static int
@@ -1243,17 +1256,15 @@ tty_keys_device_attributes(struct tty *tty, const char *buf, size_t len,
     size_t *size)
 {
 	struct client	*c = tty->client;
+	int		*features = &c->term_features;
 	u_int		 i, n = 0;
-	char		 tmp[64], *endptr, p[32] = { 0 }, *cp, *next;
+	char		 tmp[128], *endptr, p[32] = { 0 }, *cp, *next;
 
 	*size = 0;
 	if (tty->flags & TTY_HAVEDA)
 		return (-1);
 
-	/*
-	 * First three bytes are always \033[>. Some older Terminal.app
-	 * versions respond as for DA (\033[?) so accept and ignore that.
-	 */
+	/* First three bytes are always \033[?. */
 	if (buf[0] != '\033')
 		return (-1);
 	if (len == 1)
@@ -1262,56 +1273,127 @@ tty_keys_device_attributes(struct tty *tty, const char *buf, size_t len,
 		return (-1);
 	if (len == 2)
 		return (1);
-	if (buf[2] != '>' && buf[2] != '?')
+	if (buf[2] != '?')
 		return (-1);
 	if (len == 3)
 		return (1);
 
 	/* Copy the rest up to a 'c'. */
-	for (i = 0; i < (sizeof tmp) - 1; i++) {
+	for (i = 0; i < (sizeof tmp); i++) {
 		if (3 + i == len)
 			return (1);
 		if (buf[3 + i] == 'c')
 			break;
 		tmp[i] = buf[3 + i];
 	}
-	if (i == (sizeof tmp) - 1)
+	if (i == (sizeof tmp))
 		return (-1);
 	tmp[i] = '\0';
 	*size = 4 + i;
 
-	/* Ignore DA response. */
-	if (buf[2] == '?')
-		return (0);
-
 	/* Convert all arguments to numbers. */
 	cp = tmp;
 	while ((next = strsep(&cp, ";")) != NULL) {
 		p[n] = strtoul(next, &endptr, 10);
 		if (*endptr != '\0')
 			p[n] = 0;
-		n++;
+		if (++n == nitems(p))
+			break;
+	}
+
+	/* Add terminal features. */
+	switch (p[0]) {
+	case 62: /* VT220 */
+	case 63: /* VT320 */
+	case 64: /* VT420 */
+		for (i = 1; i < n; i++) {
+			log_debug("%s: DA feature: %d", c->name, p[i]);
+			if (p[i] == 4)
+				tty_add_features(features, "sixel", ",");
+		}
+		break;
+	}
+	log_debug("%s: received primary DA %.*s", c->name, (int)*size, buf);
+
+	tty_update_features(tty);
+	tty->flags |= TTY_HAVEDA;
+
+	return (0);
+}
+
+/*
+ * Handle secondary device attributes input. Returns 0 for success, -1 for
+ * failure, 1 for partial.
+ */
+static int
+tty_keys_device_attributes2(struct tty *tty, const char *buf, size_t len,
+    size_t *size)
+{
+	struct client	*c = tty->client;
+	int		*features = &c->term_features;
+	u_int		 i, n = 0;
+	char		 tmp[128], *endptr, p[32] = { 0 }, *cp, *next;
+
+	*size = 0;
+	if (tty->flags & TTY_HAVEDA2)
+		return (-1);
+
+	/* First three bytes are always \033[>. */
+	if (buf[0] != '\033')
+		return (-1);
+	if (len == 1)
+		return (1);
+	if (buf[1] != '[')
+		return (-1);
+	if (len == 2)
+		return (1);
+	if (buf[2] != '>')
+		return (-1);
+	if (len == 3)
+		return (1);
+
+	/* Copy the rest up to a 'c'. */
+	for (i = 0; i < (sizeof tmp); i++) {
+		if (3 + i == len)
+			return (1);
+		if (buf[3 + i] == 'c')
+			break;
+		tmp[i] = buf[3 + i];
+	}
+	if (i == (sizeof tmp))
+		return (-1);
+	tmp[i] = '\0';
+	*size = 4 + i;
+
+	/* Convert all arguments to numbers. */
+	cp = tmp;
+	while ((next = strsep(&cp, ";")) != NULL) {
+		p[n] = strtoul(next, &endptr, 10);
+		if (*endptr != '\0')
+			p[n] = 0;
+		if (++n == nitems(p))
+			break;
 	}
 
 	/* Add terminal features. */
 	switch (p[0]) {
 	case 41: /* VT420 */
-		tty_add_features(&c->term_features, "margins,rectfill", ",");
+		tty_add_features(features, "margins,rectfill", ",");
 		break;
 	case 'M': /* mintty */
-		tty_default_features(&c->term_features, "mintty", 0);
+		tty_default_features(features, "mintty", 0);
 		break;
 	case 'T': /* tmux */
-		tty_default_features(&c->term_features, "tmux", 0);
+		tty_default_features(features, "tmux", 0);
 		break;
 	case 'U': /* rxvt-unicode */
-		tty_default_features(&c->term_features, "rxvt-unicode", 0);
+		tty_default_features(features, "rxvt-unicode", 0);
 		break;
 	}
 	log_debug("%s: received secondary DA %.*s", c->name, (int)*size, buf);
 
 	tty_update_features(tty);
-	tty->flags |= TTY_HAVEDA;
+	tty->flags |= TTY_HAVEDA2;
 
 	return (0);
 }
@@ -1325,6 +1407,7 @@ tty_keys_extended_device_attributes(struct tty *tty, const char *buf,
     size_t len, size_t *size)
 {
 	struct client	*c = tty->client;
+	int		*features = &c->term_features;
 	u_int		 i;
 	char		 tmp[128];
 
@@ -1365,13 +1448,13 @@ tty_keys_extended_device_attributes(struct tty *tty, const char *buf,
 
 	/* Add terminal features. */
 	if (strncmp(tmp, "iTerm2 ", 7) == 0)
-		tty_default_features(&c->term_features, "iTerm2", 0);
+		tty_default_features(features, "iTerm2", 0);
 	else if (strncmp(tmp, "tmux ", 5) == 0)
-		tty_default_features(&c->term_features, "tmux", 0);
+		tty_default_features(features, "tmux", 0);
 	else if (strncmp(tmp, "XTerm(", 6) == 0)
-		tty_default_features(&c->term_features, "XTerm", 0);
+		tty_default_features(features, "XTerm", 0);
 	else if (strncmp(tmp, "mintty ", 7) == 0)
-		tty_default_features(&c->term_features, "mintty", 0);
+		tty_default_features(features, "mintty", 0);
 	log_debug("%s: received extended DA %.*s", c->name, (int)*size, buf);
 
 	free(c->term_type);
diff --git a/tty-term.c b/tty-term.c
index 8c3e8e8d..4e9b7799 100644
--- a/tty-term.c
+++ b/tty-term.c
@@ -268,6 +268,7 @@ static const struct tty_term_code_entry tty_term_codes[] = {
 	[TTYC_SETRGBF] = { TTYCODE_STRING, "setrgbf" },
 	[TTYC_SETULC] = { TTYCODE_STRING, "Setulc" },
 	[TTYC_SE] = { TTYCODE_STRING, "Se" },
+	[TTYC_SXL] =  { TTYCODE_FLAG, "Sxl" },
 	[TTYC_SGR0] = { TTYCODE_STRING, "sgr0" },
 	[TTYC_SITM] = { TTYCODE_STRING, "sitm" },
 	[TTYC_SMACS] = { TTYCODE_STRING, "smacs" },
@@ -456,6 +457,9 @@ tty_term_apply_overrides(struct tty_term *term)
 		a = options_array_next(a);
 	}
 
+	/* Log the SIXEL flag. */
+	log_debug("SIXEL flag is %d", !!(term->flags & TERM_SIXEL));
+
 	/* Update the RGB flag if the terminal has RGB colours. */
 	if (tty_term_has(term, TTYC_SETRGBF) &&
 	    tty_term_has(term, TTYC_SETRGBB))
diff --git a/tty.c b/tty.c
index 1394075d..43a2961f 100644
--- a/tty.c
+++ b/tty.c
@@ -299,9 +299,9 @@ tty_start_timer_callback(__unused int fd, __unused short events, void *data)
 	struct client	*c = tty->client;
 
 	log_debug("%s: start timer fired", c->name);
-	if ((tty->flags & (TTY_HAVEDA|TTY_HAVEXDA)) == 0)
+	if ((tty->flags & (TTY_HAVEDA|TTY_HAVEDA2|TTY_HAVEXDA)) == 0)
 		tty_update_features(tty);
-	tty->flags |= (TTY_HAVEDA|TTY_HAVEXDA);
+	tty->flags |= (TTY_HAVEDA|TTY_HAVEDA2|TTY_HAVEXDA);
 }
 
 void
@@ -363,12 +363,14 @@ tty_send_requests(struct tty *tty)
 		return;
 
 	if (tty->term->flags & TERM_VT100LIKE) {
-		if (~tty->flags & TTY_HAVEDA)
+		if (~tty->term->flags & TTY_HAVEDA)
+			tty_puts(tty, "\033[c");
+		if (~tty->flags & TTY_HAVEDA2)
 			tty_puts(tty, "\033[>c");
 		if (~tty->flags & TTY_HAVEXDA)
 			tty_puts(tty, "\033[>q");
 	} else
-		tty->flags |= (TTY_HAVEDA|TTY_HAVEXDA);
+		tty->flags |= (TTY_HAVEDA|TTY_HAVEDA2|TTY_HAVEXDA);
 }
 
 void