This page contains the list of deprecations and important or breaking changes for Vault 1.6.1 compared to 1.6.0. Please read it carefully.
Due to the known issue, Transform Secrets Engine users are recommended to upgrade to version 1.6.4.
»Transform Storage Upgrades Fixed
The Transform Secrets Engine storage upgrade introduced in 1.6.0 introduced malformed configuration for transformations configured earlier than 1.6.0, resulting in an error using these transformations if Vault is restarted after the upgrade. This issue exists on Vault 1.6.0 through 1.6.3, and is fixed in Vault 1.6.4 and 1.7.0. Transformations configured on 1.6.0 or higher are unaffected.