Apache Iceberg 1.12.0 drops Spark 3.4 and Flink 2.0 support

Apache Iceberg 1.12.0, the latest release of the open table format, removes support for Spark 3.4 and Flink 2.0, according to the project's own release notes. The project's releases page dates the release to September 29, 2026, while a Dremio upgrade guide gives September 30. The sources do not explain the one-day difference.

The release notes list the removal of Spark 3.4 support and Flink 2.0 support, along with a batch of deprecated APIs and the removal of position delete files that carry row data. The download list offers Flink 2.3, 2.2, 2.1 and 1.20 runtime jars, plus Spark 3.5, 4.0 and 4.1. Dremio's Alex Merced writes that the supported Spark lines are 3.5.9, 4.0.4 and 4.1.3, and that Spark 4.2 work is included only in the source release.

Dremio also says existing position-delete files with row data stay readable, but two maintenance operations, rewrite_position_delete_files and rewrite_table_path, now fail when they meet them. The Apache notes separately flag a behavior change: the default AWS SDK HTTP client moved to Apache HttpClient 5, so users who supply AWS dependencies themselves must switch artifacts.

Dremio describes the release as broad, citing more than 800 merged changes in the changelog, a figure we have not checked. It highlights Hilbert-curve clustering for the rewrite_data_files action and REST catalog changes such as delegating DROP TABLE PURGE to the catalog service. Dremio also says work on format version 4 is groundwork and not ready for production tables.

The removals of Spark 3.4 and Flink 2.0 are confirmed by the Apache project and by Dremio. The feature descriptions, the change count and the upgrade advice come from Dremio, a vendor that sells Iceberg-based products, and we have not independently verified them against the project's full changelog.

Teams that still run Spark 3.4 jobs or Flink 2.0 pipelines cannot move to 1.12 without first changing engine versions. Dremio advises inventorying engines, delete files and custom code that uses removed APIs, then testing before rolling out.

Revised 16 October 2026: Guth re-read the original sources and rewrote this article. Correction: the earlier version said Apache Iceberg 1.12.0 arrived on September 30, 2026. The Apache Iceberg project's releases page says it was released on September 29, 2026; the Dremio guide the earlier version relied on gives September 30. The earlier version remains available as revision 1.