# Rook v1.21.1

> Storage & Data · 2026-10-26

A maintenance release with correctness and performance improvements, new configuration capabilities, enforced secure messaging, and an upgrade-time storage-class migration requirement. Helm upgrades to `v1.21` require the existing `storageclass` to be deleted first.

## Action needed
- **[breaking]** Secure `msgr2` mode for monitor connections
  - Monitor connections now enforce secure `msgr2` mode.
- **[breaking]** OSD device discovery exclusions
  - OSD device discovery now skips `nbd`, `drbd`, and `zram` devices.

## Check if affected
- **[breaking]** `storageclass` deletion before Helm upgrade to `v1.21`
  - Applies if you upgrade to `v1.21` with Helm.
  - The `storageclass` must be deleted before a Helm upgrade to `v1.21`.

## Other recorded changes
- 14 (value_changed 7, added 3, default_changed 2, defect_corrected 2)

[Full analysis](https://ratatosk.io/en/releases/rook/v1.21.1)

[Original release notes](https://github.com/rook/rook/releases/tag/v1.21.1)