End of availability doens't mean end of support. It just means they won't be selling it anymore. for EOA/EOS dates check hwu.netapp.com not the IMT. End of support looks to be 12-Dec-2024
But looks to be that no new versions of ONTAP will support it after December 2020. So... after 9.9? something like that if I had to guess.
The BES-53248 is the direct replacement.