diff --git a/README.md b/README.md
index 61418c2..93a5449 100644
--- a/README.md
+++ b/README.md
@@ -9,7 +9,7 @@ Prerequisites
 You must install, the latest version of InterSystems IRIS DB-API Python driver
 
 ```shell
-pip3 install intersystems_irispython-3.2.0-py3-none-any.whl
+pip3 install https://github.com/intersystems-community/intersystems-irispython/releases/download/3.7.3/intersystems_iris-3.7.3-py3-none-any.whl
 ```
 
 Install and usage
diff --git a/django_iris/introspection.py b/django_iris/introspection.py
index f4837df..112f618 100644
--- a/django_iris/introspection.py
+++ b/django_iris/introspection.py
@@ -6,6 +6,8 @@
 from django.db.models import Index
 from django.utils.datastructures import OrderedSet
 
+MAXLEN = 65535
+
 FieldInfo = namedtuple(
     'FieldInfo', BaseFieldInfo._fields + ('auto_increment', ))
 
@@ -94,10 +96,9 @@ def get_table_description(self, cursor, table_name):
         description = [
             FieldInfo(
                 name,
-                'longvarchar'
-                if data_type == 'varchar' and length == '-1' else data_type,
-                None,
-                length,
+                'longvarchar' if data_type == 'varchar' and length == '-1' else data_type,
+                MAXLEN if not isinstance(length, int) or data_type != 'varchar' else length,
+                MAXLEN if not isinstance(length, int) or data_type != 'varchar' else length,
                 precision,
                 scale,
                 isnull == 'YES',
diff --git a/django_iris/operations.py b/django_iris/operations.py
index 3f107b3..bd1d1c4 100644
--- a/django_iris/operations.py
+++ b/django_iris/operations.py
@@ -8,7 +8,10 @@
 from datetime import date, datetime,timedelta
 from django.utils.encoding import force_str
 from django.utils.dateparse import parse_date, parse_datetime, parse_time
-from django.db.backends.base.base import timezone_constructor
+try:
+    from django.db.backends.base.base import timezone_constructor # Django 4.2
+except ImportError:
+    from django.utils.timezone import timezone as timezone_constructor # Django 5+
 
 from .utils import BulkInsertMapper
 
diff --git a/requirements.txt b/requirements.txt
index 2155958..8ed432e 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1 +1 @@
-https://github.com/intersystems-community/intersystems-irispython/releases/download/3.6.3/intersystems_iris-3.6.3-py3-none-any.whl
\ No newline at end of file
+https://github.com/intersystems-community/intersystems-irispython/releases/download/3.7.3/intersystems_iris-3.7.3-py3-none-any.whl
\ No newline at end of file