diff --git a/rel2graph/core/converter.py b/rel2graph/core/converter.py
index 5a74190..518d3b2 100644
--- a/rel2graph/core/converter.py
+++ b/rel2graph/core/converter.py
@@ -268,7 +268,7 @@ def cleanup_process_state():
 class Converter:
     """The converter handles the whole conversion pipeline.  """
 
-    def __init__(self, schema: str, iterator: ResourceIterator, neo4j_uri: str, neo4j_auth: Auth, num_workers: int = max(mp.cpu_count()-2, 1), serialize: bool = False, batch_size: int = 5000) -> None:
+    def __init__(self, schema: str, iterator: ResourceIterator, neo4j_uri: str, neo4j_auth: Auth, num_workers: int = None, serialize: bool = False, batch_size: int = 5000) -> None:
         """Initialises a converter. Note that this is a singleton and only the most recent instantiation is valid.
         
         Args:
@@ -281,8 +281,13 @@ def __init__(self, schema: str, iterator: ResourceIterator, neo4j_uri: str, neo4
                 and committed to the graph in the same order as they are returned by the iterator. Note that you can't set both serialize to true and set num_workers > 1. (default: False)
             batch_size: The batch size for the parallel processing. (default: 5000)
         """
-        if serialize and num_workers > 1:
-            raise ValueError("You can't use serialization and parallel processing (num_workers > 1) at the same time.")
+        if serialize:
+            if num_workers is not None and num_workers > 1:
+                raise ValueError("You can't use serialization and parallel processing (num_workers > 1) at the same time.")
+            else:
+                num_workers = 1
+        elif num_workers is None:
+            num_workers = mp.cpu_count() - 2
         
         # Verify connection to neo4j
         self._neo4j_uri = neo4j_uri
diff --git a/rel2graph/core/factories/matcher.py b/rel2graph/core/factories/matcher.py
index b62533e..5b946fd 100644
--- a/rel2graph/core/factories/matcher.py
+++ b/rel2graph/core/factories/matcher.py
@@ -89,7 +89,7 @@ def match(self, resource: Resource) -> List[Node]:
             else:
                 value = "r"
             clause = _match_clause("n", (tuple(parsed_labels), *keys), value)
-            clause, params = cypher_join("UNWIND $data AS r", clause, "RETURN LABELS(n) as labels, n as properties, elementId(n) as identity", data=[values])
+            clause, params = cypher_join("UNWIND $data AS r", clause, "RETURN LABELS(n) as labels, n as properties, id(n) as identity", data=[values])
 
             with Matcher.graph_driver.session() as session:
                 match_list = session.run(clause, **params).data()
diff --git a/tests/integration/helpers.py b/tests/integration/helpers.py
index b637250..44c931a 100644
--- a/tests/integration/helpers.py
+++ b/tests/integration/helpers.py
@@ -55,16 +55,18 @@ def num_relationships(session):
 def get_nodes(session, labels=[]):
     if not isinstance(labels, list) and not isinstance(labels, tuple):
         labels = [labels]
-    res = session.run("MATCH (n{}) RETURN LABELS(n) as labels, n as properties, elementId(n) as identity".format(":" + ":".join(labels) if len(labels) else "")).data()
+    # TODO: id() is deprecated, in the future we need to move to something else
+    res = session.run("MATCH (n{}) RETURN LABELS(n) as labels, n as properties, id(n) as identity".format(":" + ":".join(labels) if len(labels) else "")).data()
     match_list = [Node.from_dict(r['labels'], r['properties'], identity=r["identity"]) for r in res]
     return match_list
 
 def get_relationships(session, types=[]):
     if not isinstance(types, list) and not isinstance(types, tuple):
         types = [types]
-    res = session.run("""MATCH (a)-[r{}]->(b) RETURN TYPE(r) as type, PROPERTIES(r) as properties, elementId(r) as identity, 
-                        LABELS(a) as start_labels, a as start_properties, elementId(a) as start,
-                        LABELS(b) as end_labels, b as end_properties, elementId(b) as end
+    # TODO: id() is deprecated, in the future we need to move to something else
+    res = session.run("""MATCH (a)-[r{}]->(b) RETURN TYPE(r) as type, PROPERTIES(r) as properties, id(r) as identity, 
+                        LABELS(a) as start_labels, a as start_properties, id(a) as start,
+                        LABELS(b) as end_labels, b as end_properties, id(b) as end
                       """.format(":" + "|".join(types) if len(types) else "")).data()
     
     match_list = [Relationship(Node.from_dict(r['start_labels'], r['start_properties'], identity=r["start"]),