AFF8020 revert from cDOT9.1 to cDOT 8.3.2P5 in-dedupe can't be turn on

Hi All,

Recently, I revert the AFF8020 from cDOT 9.1 to cDOT 8.3.2P5, but there is some strange condition afterward.

The System Manager and Command line can't enable inline dedupe

The error as below:

DATA ONTAP APF failed: Inline Deduplication requires an effective cluster version of DATA ONTAP 8.3.2 or later

Please help to share your experience to see how it solves.

Many thanks.

Tony Wu