●Change8

Migrating to Ray ray-2.52.0

Version ray-2.52.0 introduces 4 breaking changes. This guide details how to update your code.

Released: 11/21/2025

4
Breaking Changes
7
Migration Steps
21
Affected Symbols

⚠️ Check Your Code

If you use any of these symbols, you need to read this guide:

read_delta_lakemap_groupsApproximateTopKRobustScalermap_batchestqdm_rayDEFAULT_ACTOR_MAX_TASKS_IN_FLIGHT_TO_MAX_CONCURRENCY_FACTORudf_modifying_row_countread_parquetparse_hive_pathStreamingPartitionStreamingRepartitionResult.from_pathpoll_workersJAX_PLATFORMSTrainControllerStateCustomRequestRouterUnityCatalog integration classesIcebergTableRayDataMetricsRayTrainMetrics

Breaking Changes

●Issue #1

Python 3.9 wheels are no longer published; projects still on Python 3.9 must upgrade to Python >=3.10 to continue receiving releases.

●Issue #2

The default value of `udf_modifying_row_count` was changed to false, which can break UDFs that previously relied on automatic row‑count modifications.

●Issue #3

The internal stats update thread was removed, which may break custom metrics listeners that expected that thread to exist.

●Issue #4

`DEFAULT_ACTOR_MAX_TASKS_IN_FLIGHT_TO_MAX_CONCURRENCY_FACTOR` was lowered to 2, potentially altering actor concurrency limits for existing workloads.

Migration Steps

  1. 1
    If you rely on UDFs that modify row counts, explicitly set `udf_modifying_row_count=True` where needed.
  2. 2
    Review and update any custom metrics listeners that depended on the removed stats update thread.
  3. 3
    Check actor definitions for concurrency assumptions; adjust `max_concurrency` if the lowered `DEFAULT_ACTOR_MAX_TASKS_IN_FLIGHT_TO_MAX_CONCURRENCY_FACTOR` impacts performance.
  4. 4
    Update Ray Train checkpoint configuration to use the new schema and replace any deprecated trainer parameters.
  5. 5
    If you want token authentication, enable it in the Ray dashboard, CLI, or client configuration and follow the security guide.
  6. 6
    Validate Iceberg write paths and schema updates against the new upsert and overwrite semantics.
  7. 7
    Run the Ray Data test suite after upgrading to ensure zero‑copy map operations and new expression types behave as expected.

Release Summary

Ray 2.x introduces token authentication, extensive Iceberg enhancements, new expression capabilities, and numerous performance improvements, while dropping Python 3.9 support and adjusting several defaults that may require migration steps.

Need More Details?

View the full release notes and all changes for Ray ray-2.52.0.

View Full Changelog