The most recent information I could find said NI MultiSim was compatible with LabVIEW, as follows:
"The LabVIEW Multisim Co-Simulation Plug-in has the following requirements:
- LabVIEW 2017, 2018, or 2019 Full or Professional Development System (32-bit)
- LabVIEW 2017, 2018, or 2019 Control Design and Simulation Module
To install the LabVIEW Multisim API Toolkit, you must already have LabVIEW 2017, 2018, or 2019 Full or Professional Development System (32-bit) installed."
There are several products that had no support in LabVIEW 2020 (though there was no announcement about this) -- some are being released with LabVIEW 2021 SP1 (soon). With a little luck, NI might include NI Multisim, too ...
Bob Schor