diff --git a/scripts/properties_to_json.py b/scripts/properties_to_json.py
index 0c71261..90146cc 100644
--- a/scripts/properties_to_json.py
+++ b/scripts/properties_to_json.py
@@ -58,6 +58,7 @@
 import csv
 import json
 import pathlib
+import re
 
 DIR = pathlib.Path(__file__).parent.parent
 CSV_PATH = DIR / "data/properties_description/"
@@ -71,6 +72,10 @@
     CSV_PATH.glob("*.csv"), key=lambda p: float(p.stem.lstrip("v")), reverse=True
 )
 
+def canonicalize(s):
+    """strips non-letters and lower-cases"""
+    return re.sub("\\W", "", s).lower()
+
 for csv_path in paths:
     version = csv_path.stem
     # header = ["Parent Type", "Property", "Type", "Description"]
@@ -85,12 +90,32 @@
         # Look for a similar existing item from a newer CodeMeta version
         for existing_item in json_items:
             if existing_item.items() >= item.items():
-                # We found an existing item, add this version to its list
+                # We found an identical existing item, add this version to its list
                 assert (
                     version not in existing_item["versions"]
                 ), f"CodeMeta {version} has duplicated property {item}"
                 existing_item["versions"].append(version)
+            # check for existing properties that have differing types or descriptions
+            # values from newer versions of properties_description.json take precedence
+            # over new ones.
+            # update the versions for these here and break to avoid duplicate rows
+            if item["Property"] == existing_item["Property"] and item["Parent Type"] == existing_item["Parent Type"]:
+                if canonicalize(item["Type"]) != canonicalize(existing_item["Type"]):
+                    # both types meaningfully differ
+                    item["versions"] = [version]
+                    json_items.append(item)
+                else:
+                    item["Type"] = existing_item["Type"]
+                    if version not in existing_item["versions"]:
+                        existing_item["versions"].append(version)
+
+                if item["Description"] != existing_item["Description"] and item["Type"] == existing_item["Type"]:
+                    item["Description"] = existing_item["Description"]
+                    if version not in existing_item["versions"]:
+                        existing_item["versions"].append(version)
+
                 break
+
         else:
             # No similar item, create a new one
             item["versions"] = [version]