Django 2.2 (LTS): What's New, Release History & Support Lifecycle

What Is New in Django 2.2

Django 2.2 is a Long Term Support (LTS) release, bringing stability and several key enhancements. This version focuses on database constraints, improved admin interfaces, and various developer experience refinements.

How does Django 2.2 improve database constraints?

This release introduces a powerful new API for defining database constraints directly from your models. You can now use CheckConstraint and UniqueConstraint classes within your model's Meta.constraints option.

In practice, this means your validation logic moves closer to the database, ensuring data integrity even if other applications access the same database. You can define complex constraints that were previously difficult to enforce at the ORM level.

from django.db import models

class Customer(models.Model):
    age = models.IntegerField()
    status = models.CharField(max_length=10)

    class Meta:
        constraints = [
            models.CheckConstraint(check=models.Q(age__gte=18), name='age_gte_18'),
            models.UniqueConstraint(fields=['status', 'age'], name='unique_status_age')
        ]

What admin customization features were added?

Django 2.2 makes the admin site more customizable through class-based configuration. The new AdminSite class allows you to override default behaviors like site headers, titles, and URLs without monkey-patching.

You can now create multiple admin site instances with different configurations, which is useful for complex projects requiring separate admin interfaces. This approach is cleaner than the previous function-based customization methods.

from django.contrib.admin import AdminSite

class CustomAdminSite(AdminSite):
    site_header = 'Custom Administration'
    site_title = 'Custom Admin Portal'
    index_title = 'Welcome to the custom admin'

custom_admin_site = CustomAdminSite(name='custom_admin')

What performance improvements should I know about?

The bulk_update() method was added, allowing you to update multiple model instances with a single query. This significantly reduces database round-trips when you need to update many objects at once.

Model saving operations became faster through optimized SQL generation. The ORM now generates more efficient INSERT and UPDATE statements, particularly noticeable when working with large datasets.

# Update multiple objects efficiently
objects_to_update = [obj1, obj2, obj3]
for obj in objects_to_update:
    obj.field = new_value

Model.objects.bulk_update(objects_to_update, ['field'])

How does HTTP response handling improve?

HttpResponse now supports context manager protocol for proper resource handling. You can use HttpResponse objects in with statements, ensuring that resources are closed properly even if exceptions occur during response processing.

The new HttpResponse.headers attribute provides a case-insensitive interface for accessing response headers. This simplifies header manipulation compared to the previous dictionary-like access.

# Using HttpResponse as context manager
with HttpResponse() as response:
    response.write('Hello')
    response.headers['X-Custom-Header'] = 'Value'
    return response