asterisk users - Jan 2021 - pjsip presence on Cisco SPA525G2 with SPA500DS

Hello,

could somebody drive me how could I make run presence reporting by BLF
feature on the Cisco SPA525G2 with SPA500DS on asterisk with pjsip
stack?

I am not able to configure asterisk side. When I run pjsip show
subscriptions inbound I see all subscriptions as dialog. Which as of
my understanding is not sufficient.

Moreover I suspect even I configure asterisk side successfully, the
SPA525G2 phones will not support it. Could somebody confirm if it is
working or not possible to achieve it using these phones?

Thanks.

Marek