just to confirm
those that have syscoin wallet.dat files from sys 2 will be able to open that dat or extract the priv key and use that on the sys 4. This is not a coin swap situation?
It's a new chain so you will not be able to open the wallet.dat, but you will be able to extract the private key and use that on Syscoin 4.0, if you are having trouble upgrading, join our discord (but make sure you don't answer direct messages even if they look like they are from legitimate users). Join the #help channel and someone can help you out.
https://discord.gg/RkK2AXD