Version 0.3.2386 frequently appears in Apple Support Community EtreCheck reports from 2019, where it was documented alongside other software installs for troubleshooting system performance and network issues. Legacy Performance In 2019, this version was noted for:
Required a stable internet connection and QR code linking with a mobile device, as "Multi-device" support was not yet a feature in this era of the desktop app. WhatsApp 0.3.2386
Are you looking to this specific legacy version, or do you need a migration guide to the latest WhatsApp Desktop client? WhatsApp™ portable - Portapps Version 0