New, improved, or changed features:

• Minifying BinaryFormatter payloads has been added
• Minifying other payload formats have been improved
• Building BinaryFormatter from a JSON text
• Adding some more gadgets, formatters, and some new payload variants (use --fullhelp to see everything)
• Easier internal testing abilities for researchers (--runmytest)
• Improved SerializersHelper
• ObjectStateFormatter formatter has been removed (LosFormatter without a key == ObjectStateFormatter)
• More flexibility for the gadgets to support new options and an init method (useful for plugins and gadget writers)
• --runallformatters option to show the result of different gadgets which support a specific formatter

To see list of all the changes since January 2020, please see https://www.mdsec.co.uk/2020/04/introducing-ysoserial-net-april-2020-improvements/