We started talking about SQLAlchemy 2.0 in Openstack most officially in August 2021:

Since then, lots of work has been done for SQLAlchemy 2.0 compatibility.  oslo.db master IIUC should be fully free of 2.0 deprecation warnings, this is the topic for that: https://review.opendev.org/q/topic:sqlalchemy-20+repo:openstack/oslo.db  however, sqlalchemy-migrate would need to be fully retired from it which hasn't happened yet.

For downstream projects, the vast majority of SQLAlchemy-related code, which is lots of session.query() calls, should not have to change except to the degree that string-based notation for object attributes is removed in favor of actual attributes, e.g. joinedload("networks") becomes joinedload(Machine.networks).

The SQLAlchemy 2.0 migration process is designed to be gradual and starts with building a 2.0 forwards-compliant application that runs under SQLAlchemy 1.4.  This process is documented at https://docs.sqlalchemy.org/en/20/changelog/migration_20.html#the-1-4-2-0-migration-path .   I think a lot of projects are already through this process and are now trying to run directly on the 2.0 release.  

On Wed, Feb 1, 2023, at 8:02 AM, Thomas Goirand wrote: