Steinberg, the creators of the VST plugin format have ceased support for Version 2 of the format. Steinberg has removed the VST2 Software Development kit from public availability and stopped licensing any new VST2 developers after October 2018. Any developer not already licensed with Steinberg may not distribute VST2 plugins.
If you make plugins with SynthEdit, this change may affect you. Plugins made with SynthEdit 32-bit are VST Version 2 plugins.
VST Version 3 plugins are not affected by this ban. To create VST Version 3 plugins use the 64-bit version of SynthEdit.
For detailed information on your responsibilities when distributing plugins you make with SynthEdit, please refer to the VST Licensing Information page. You can find a information there on getting your own VST license, which is free. Note that SynthEdit uses only the "Proprietary Steinberg VST 3" license.