What are the latest rules regarding WSPR exchanges and DXCC qualifying "QSOs"? I hear a rumour that ARRL will accept confirmed WSPR exchanged reports (he hears you and posts a report and you hear him and post a report to the database/by QSL card?) as a valid DXCC exchange. I.e. this is a mutual exchange of reports using, for example, WSPR2 and not necessarily the QSO mode in WSJT.

Is this correct?

Certainly an exchange of details via WSPR contains far more information than a DX contest exchange on HF which IS valid for DXCC.