Compatiblity notes has been added

Author: bma13

README.md

@@ -23,3 +23,9 @@ For steps on how to deploy and use YDB Kubernetes Operator, please refer to [doc
 ## Development
 
 Refer to the operator [development docs](./docs).
+
+## Compatibility Notes
+
+Version 0.7.0 includes major dependency upgrades that may affect compatibility with older Kubernetes clusters. The operator has been migrated from controller-runtime v0.14.1 to v0.22.4 and now requires Go 1.24 (previously 1.20). Kubernetes libraries have been updated from v0.26.15 to v0.34.x (k8s.io/api, k8s.io/apimachinery, k8s.io/client-go, k8s.io/kubectl), and k8s.io/utils has been aligned with Kubernetes 1.34 compatibility.
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+Due to these changes, running the operator on significantly older Kubernetes versions may lead to unexpected behavior or incompatibilities. The operator has been tested with Kubernetes v1.20 and v1.34. It is strongly recommended to use Kubernetes versions compatible with the v1.34 client libraries.