- Trident 21.04 and 21.07
- Astra Trident 21.10 and higher
- Kubernetes 1.21 and higher
The main reason it's still there is backwards compatibility with Kubernetes versions older than 1.21, specifically to still support 1.17.
As long as Trident cannot support 1.25 yet (i.e. until its release), leaving in this compatibility covers more ground.
See Trident Github issue #661 for more information on upcoming changes.