does this mean that banks will no longer accept these notes?

I think it means that Banks (other than the SNB) are no longer required to accept these notes. But it could be something subject to a fee. YMMV.

4. Kann ich meine alten Nötli auch bei meiner Hausbank umtauschen?

Ja. Das bestätigt auch ein Sprecher der Raiffeisen Schweiz. Alte Banknoten könnten jederzeit auch am Schalter einer Hausbank in neue umgetauscht werden, sagt er.

So sounds like banks do accept it for exchange - and most likely only do it free of charge when done at the counter of bank you have account in.

Above is one bank confirming they can do exchange.

SBB would accept old series 8 bills - until 31.Oct.2021 , there is no word they'd act as exchange counter

The post office will accept them until October 31st.

There's no rush to change the old bills, they don't lapse. With inflation and interest rates where they are, cash is actually slightly profitable (ignoring the risks naturally inherent in holding paper, like destruction by fire).

The following banks will accept them indefinitely, as they accept the other series since #6. Older series can no longer be exchanged but they may have value for collectors.
I'm not entirely sure, but I'd expect the various agencies of the cantonal banks listed below to accept them as well.

"My" Raiffeisen bank says that they accept them still, to exchange for the new ones. Amounts above 5k on appointment only though.