If you are streaming to Twitch, attending Zoom meetings, or recording a podcast, you should use ManyCam 8 or OBS Studio. The stability, compatibility, and security are non-negotiable.
The biggest selling point of 2.3.21 today is its efficiency. A clean install of this version takes less than 25 MB of RAM and uses negligible CPU. If you are trying to stream on a netbook or an old Pentium machine, modern ManyCam will lag; 2.3.21 will not. ManyCam 2.3.21
Despite its small installation footprint, version 2.3.21 includes essential tools for live video production. 1. Multi-Source Video Switching If you are streaming to Twitch, attending Zoom
If you need a free, lightweight virtual camera for an old Windows 7 machine or to experiment with basic PiP, ManyCam 2.3.21 is fine. For current use, consider (free, more powerful) or the latest ManyCam Free (but now includes ads and watermarks). A clean install of this version takes less