diff --git a/pyPRMS/metadata/metadata.py b/pyPRMS/metadata/metadata.py
index e095115..50390f3 100644
--- a/pyPRMS/metadata/metadata.py
+++ b/pyPRMS/metadata/metadata.py
@@ -117,8 +117,12 @@ def __filter_by_version(self, elem: xmlET.Element, name: str,
 
         meta_dict[name] = {}
 
-        try:
-            var_version = Version(elem.attrib.get('version'))
+        # Missing version/deprecated attributes are checked explicitly:
+        # relying on Version(None) to raise is fragile (packaging < 26.3
+        # raised TypeError, packaging >= 26.3 raises InvalidVersion).
+        version_attr = elem.attrib.get('version')
+        if version_attr is not None:
+            var_version = Version(version_attr)
 
             if var_version > req_version:
                 if self.__verbose:   # pragma: no cover
@@ -126,11 +130,10 @@ def __filter_by_version(self, elem: xmlET.Element, name: str,
                 del meta_dict[name]
                 return True
             meta_dict[name]['version'] = str(var_version)
-        except TypeError:
-            pass
 
-        try:
-            depr_version = Version(elem.attrib.get('deprecated'))
+        depr_attr = elem.attrib.get('deprecated')
+        if depr_attr is not None:
+            depr_version = Version(depr_attr)
 
             if depr_version <= req_version:
                 if self.__verbose:   # pragma: no cover
@@ -138,8 +141,6 @@ def __filter_by_version(self, elem: xmlET.Element, name: str,
                 del meta_dict[name]
                 return True
             meta_dict[name]['deprecated'] = depr_version
-        except TypeError:
-            pass
 
         return False
 
diff --git a/pyproject.toml b/pyproject.toml
index 1f665dd..682a984 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -23,6 +23,7 @@ dependencies = ["cartopy",
     "netCDF4!=1.7.4",
     "networkx>=2",
     "numpy",
+    "packaging",
     "pandas",
     "pyproj",
     "rich",
diff --git a/tests/func/test_MetaData.py b/tests/func/test_MetaData.py
index 5caaf7d..07316b7 100644
--- a/tests/func/test_MetaData.py
+++ b/tests/func/test_MetaData.py
@@ -26,3 +26,16 @@ def test_metadata_version5(self):
     def test_metadata_version4(self):
         prms_meta = MetaData(version='4', verbose=True).metadata
         assert prms_meta['parameters'].get('soilzone_aet_flag', None) is None
+
+    def test_metadata_no_version_attributes(self):
+        """Entries lacking version/deprecated XML attributes are retained.
+
+        Regression test: packaging >= 26.3 raises InvalidVersion instead of
+        TypeError for Version(None), which crashed MetaData for any element
+        without these attributes.
+        """
+        prms_meta = MetaData(version='5.2.1.1', verbose=True).metadata
+        # cascade_flag has neither a version nor a deprecated attribute
+        assert 'cascade_flag' in prms_meta['control']
+        # nhruOutON_OFF has only a deprecated attribute
+        assert 'nhruOutON_OFF' in prms_meta['control']