diff --git a/ChangeLog b/ChangeLog
index 28c213b3d6..0626bd57c9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,4 +1,4 @@
-10/1/23 started 8.15
+18/10/23 8.15.0-rc1
 
 - add support for target_clones attribute [lovell]
 	* use with (un)premultiply for ~10% perf gain on AVX CPUs
diff --git a/libvips/foreign/exif.c b/libvips/foreign/exif.c
index 1b7cc77a6b..b11b604331 100644
--- a/libvips/foreign/exif.c
+++ b/libvips/foreign/exif.c
@@ -296,7 +296,10 @@ vips_exif_to_s(ExifData *ed, ExifEntry *entry, VipsBuf *buf)
 	int iv;
 	ExifRational rv;
 	ExifSRational srv;
-	char txt[256];
+	char txt[256], *value;
+
+	value = g_utf8_make_valid(
+		exif_entry_get_value(entry, txt, 256), -1);
 
 	if (entry->format == EXIF_FORMAT_ASCII) {
 		/* libexif does not null-terminate strings. Copy out and add
@@ -306,7 +309,10 @@ vips_exif_to_s(ExifData *ed, ExifEntry *entry, VipsBuf *buf)
 
 		memcpy(txt, entry->data, len);
 		txt[len] = '\0';
-		vips_buf_appendf(buf, "%s ", txt);
+
+		char *utf8 = g_utf8_make_valid(txt, -1);
+		vips_buf_appendf(buf, "%s ", utf8);
+		g_free(utf8);
 	}
 	else if (entry->components < 10 &&
 		!vips_exif_get_int(ed, entry, 0, &iv)) {
@@ -332,14 +338,15 @@ vips_exif_to_s(ExifData *ed, ExifEntry *entry, VipsBuf *buf)
 		}
 	}
 	else
-		vips_buf_appendf(buf, "%s ",
-			exif_entry_get_value(entry, txt, 256));
+		vips_buf_appendf(buf, "%s ", value);
 
 	vips_buf_appendf(buf, "(%s, %s, %lu components, %d bytes)",
-		exif_entry_get_value(entry, txt, 256),
+		value,
 		exif_format_get_name(entry->format),
 		entry->components,
 		entry->size);
+
+	g_free(value);
 }
 
 typedef struct _VipsExifParams {
diff --git a/libvips/foreign/heifsave.c b/libvips/foreign/heifsave.c
index bf796ab3bd..ffd50a6c2b 100644
--- a/libvips/foreign/heifsave.c
+++ b/libvips/foreign/heifsave.c
@@ -465,10 +465,16 @@ vips_foreign_save_heif_write(struct heif_context *ctx,
 
 	struct heif_error error;
 
+#ifdef HAVE_HEIF_ERROR_SUCCESS
+	error = heif_error_success;
+#else
 	error.code = heif_error_Ok;
+#endif /*HAVE_HEIF_ERROR_SUCCESS*/
+
 	if (vips_target_write(heif->target, data, length)) {
 		error.code = heif_error_Encoding_error;
 		error.subcode = heif_suberror_Cannot_write_output_data;
+		error.message = "Cannot write output data";
 	}
 
 	return error;
diff --git a/meson.build b/meson.build
index 31b4f6a1a3..ddf8f835ea 100644
--- a/meson.build
+++ b/meson.build
@@ -379,8 +379,8 @@ if libtiff_dep.found()
     endif
 endif
 
-# 2.48 is the first version to not use libcroco, an unmaintained CSS parser
-librsvg_dep = dependency('librsvg-2.0', version: '>=2.48.0', required: get_option('rsvg'))
+# 2.40.3 so we get the UNLIMITED open flag
+librsvg_dep = dependency('librsvg-2.0', version: '>=2.40.3', required: get_option('rsvg'))
 cairo_dep = dependency('cairo', version: '>=1.2', required: get_option('rsvg'))
 librsvg_found = librsvg_dep.found() and cairo_dep.found()
 if librsvg_found
@@ -505,6 +505,10 @@ if libheif_dep.found()
     if libheif_dep.version().version_compare('>=1.13.0')
         cfg_var.set('HAVE_HEIF_INIT', '1')
     endif
+    # heif_error_success added in 1.17.0
+    if libheif_dep.version().version_compare('>=1.17.0')
+        cfg_var.set('HAVE_HEIF_ERROR_SUCCESS', '1')
+    endif
 endif
 
 libjxl_dep = dependency('libjxl', version: '>=0.6', required: get_option('jpeg-xl'))