diff --git a/CHANGELOG.txt b/CHANGELOG.txt
index 71784a80..925bdc81 100644
--- a/CHANGELOG.txt
+++ b/CHANGELOG.txt
@@ -16,6 +16,12 @@ You should have received a copy of the GNU General Public License
 along with this program.  If not, see
 <http://www.gnu.org/licenses/>.
 
+Changes in v2023.5.1:
+  1/ Tab labels use two lines instead of eliding to fit width.
+  2/ Ignore NULL bytes in some phone images' Exif comment values.
+  3/ Italian localisation is complete.
+  4/ Other minor improvements and bug fixes.
+
 Changes in v2023.5.0:
   1/ Latitude & longitude values no longer have comma separator.
   2/ All numeric values are localised, e.g. to use decimal comma.
diff --git a/src/photini/__init__.py b/src/photini/__init__.py
index 12494106..f8717376 100644
--- a/src/photini/__init__.py
+++ b/src/photini/__init__.py
@@ -1,4 +1,4 @@
 """Full documentation is at https://photini.readthedocs.io/"""
 
 __version__ = '2023.5.1'
-build = '2719 (e80171b)'
+build = '2722 (64e9222)'
diff --git a/src/photini/exiv2.py b/src/photini/exiv2.py
index 4efd7cc7..7c04bd12 100644
--- a/src/photini/exiv2.py
+++ b/src/photini/exiv2.py
@@ -335,25 +335,33 @@ def get_exif_comment(self, tag, datum):
             if charset != exiv2.CharsetId.undefined:
                 logger.warning('%s: %s: unknown charset', self._name, tag)
                 raw_value = data
+        result = None
         for encoding in encodings:
             result = self.decode_string(tag, raw_value, encoding)
             if result:
-                return result
-        detector = chardet.universaldetector.UniversalDetector()
-        for i in range(0, len(raw_value), 100):
-            detector.feed(raw_value[i:i+100])
-            if detector.done:
                 break
-        detector.close()
-        encoding = detector.result['encoding']
-        if encoding:
-            result = self.decode_string(tag, raw_value, encoding)
-            if result:
-                return result
-        logger.error(
-            '%s: %s: %d bytes binary data will be deleted when metadata'
-            ' is saved', self._name, tag, value.size())
-        return None
+        else:
+            detector = chardet.universaldetector.UniversalDetector()
+            for i in range(0, len(raw_value), 100):
+                detector.feed(raw_value[i:i+100])
+                if detector.done:
+                    break
+            detector.close()
+            encoding = detector.result['encoding']
+            if encoding:
+                result = self.decode_string(tag, raw_value, encoding)
+        if result and '\0' in result:
+            # terminating NULLs are allowed
+            result = result.strip('\0')
+            if '\0' in result:
+                # NULLs within the string are not allowed
+                result = None
+        if not result:
+            logger.error(
+                '%s: %s: %d bytes binary data will be deleted when metadata'
+                ' is saved', self._name, tag, value.size())
+            return None
+        return result
 
     def get_exif_value(self, tag):
         datum = self._exifData.findKey(exiv2.ExifKey(tag))
diff --git a/src/photini/types.py b/src/photini/types.py
index 7f3b1269..17f2615a 100644
--- a/src/photini/types.py
+++ b/src/photini/types.py
@@ -690,10 +690,10 @@ def get_type(cls, key, value):
 
     @classmethod
     def from_exiv2(cls, file_value, tag):
+        file_value = file_value or {}
         if isinstance(file_value, (list, tuple)):
             # "legacy" list of string values
             file_value = dict(zip(cls.legacy_keys, file_value))
-        file_value = file_value or {}
         for key, value in file_value.items():
             file_value[key] = cls.get_type(key, value).from_exiv2(value, tag)
         return cls(file_value)