diff --git a/capa/render/result_document.py b/capa/render/result_document.py
index 03ea245f..ef899fd2 100644
--- a/capa/render/result_document.py
+++ b/capa/render/result_document.py
@@ -80,7 +80,7 @@ class Analysis(Model):
 class Metadata(Model):
     timestamp: datetime.datetime
     version: str
-    argv: Optional[Tuple[str, ...]] = None
+    argv: Optional[Tuple[str, ...]]
     sample: Sample
     analysis: Analysis
 
diff --git a/scripts/bulk-process.py b/scripts/bulk-process.py
index 5ca3f6d1..264e7719 100644
--- a/scripts/bulk-process.py
+++ b/scripts/bulk-process.py
@@ -144,8 +144,7 @@ def get_capa_results(args):
     meta.analysis.layout = capa.main.compute_layout(rules, extractor, capabilities)
 
     doc = rd.ResultDocument.from_capa(meta, rules, capabilities)
-
-    return {"path": path, "status": "ok", "ok": doc.dict(exclude_none=True)}
+    return {"path": path, "status": "ok", "ok": doc.model_dump()}
 
 
 def main(argv=None):
@@ -214,9 +213,7 @@ def main(argv=None):
             if result["status"] == "error":
                 logger.warning(result["error"])
             elif result["status"] == "ok":
-                results[result["path"].as_posix()] = rd.ResultDocument.parse_obj(result["ok"]).model_dump_json(
-                    exclude_none=True
-                )
+                results[result["path"].as_posix()] = rd.ResultDocument.model_validate(result["ok"]).model_dump_json()
             else:
                 raise ValueError(f"unexpected status: {result['status']}")