Hi. *tl;dr* In Airflow 3.2 a breaking change introduced with [email]email_backend no longer respected. Github issue: https://github.com/apache/airflow/issues/65012 (closed, but it wasn't resolved)
[email]email_backend Airflow configuration property should be one of the most usable properties in Airflow 2 (prior to Airflow 3), and it is likely not all (most of) Airflow users didn't yet migrate to SmtpNotifiers in Airflow 3.1 (since there was backward compatibility maintained). What is the community's stance on this? Was this breaking change (in minor Airflow version) introduced accidentally? If this was intended breaking change, should we then at least have a note about it in Release Notes for Airflow 3.2.0 (currently there is no mentioning of this)? https://airflow.apache.org/docs/apache-airflow/stable/release_notes.html#airflow-3-2-0-2026-04-07 *Background:* In Airflow 3.0 email/email_on_retry/email_on_retry task parameters were deprecated (in favor of SmtpNotifier(s)), DAGs using these parameters will have warning messages but still continue to work using [email]email_backend and [email]email_conn_id Airflow configuration properties to send emails: https://github.com/apache/airflow/blob/3.0.6/task-sdk/src/airflow/sdk/bases/operator.py#L1048 https://github.com/apache/airflow/blob/3.0.6/task-sdk/src/airflow/sdk/execution_time/task_runner.py#L1157 https://github.com/apache/airflow/blob/3.0.6/airflow-core/src/airflow/utils/email.py#L72 Since Airflow 3.2.0, mails on email_on_retry and email_on_failure are sent using SmtpNotifier, bypassing the configured email_backend (and email_conn_id - this was fixed later). https://github.com/apache/airflow/blob/3.2.0/task-sdk/src/airflow/sdk/execution_time/task_runner.py#L1612 https://github.com/apache/airflow/pull/65072 There was an open issue https://github.com/apache/airflow/issues/65012 about this, and it was closed with partial fix "fix stmp email callback to use email_conn_id". Overall this change - stop respecting [email]email_backend in email_on_retry/email_on_retry, forces Airflow users to update their Dags to use on_*_callback(s) before migrating. -- Eugene
