The end-of-life for Postgres 10 on Heroku is closer and closer, but I still have a legacy project on Django 1.9 using it there. Is it possible to migrate to Postgres 11 without troubles?
Going by the documentation:
Django supports PostgreSQL 9.0 and higher. It requires the use of psycopg2 2.4.5 or higher (or 2.5+ if you want to use django.contrib.postgres).
https://docs.djangoproject.com/en/1.8/ref/databases/#postgresql-notes
The current psycopg2 implementation supports:
- Python versions from 3.6 to 3.10
- PostgreSQL server versions from 7.4 to 14
- PostgreSQL client library version from 9.1
The earliest mentions of Postgres 11 in psycopg2 appear around 2.7.x, with 2.8 explicitly mentioning:
Dropped support for Python 2.6, 3.2, 3.3.
Wheel package compiled against OpenSSL 1.0.2r and PostgreSQL 11.2 libpq.
https://www.psycopg.org/docs/news.html#what-s-new-in-psycopg-2-8
So, the problem will be somewhere around psycopg, if anything. If you can run your Django project on Python 3.4+ with psycopg 2.8+, there should be no reason why it doesn't work. Older versions of psycopg2 may well work with Postgres 11+ just fine as well. You should simply test that on a local environment (e.g. Docker).