Hello there, In this update I have worked on Voucher Codes. This update will make a new file called VoucherCodes.yml. In there is now where you put your voucher codes. So if you have voucher codes in your config you will need to remake them in this new file.
Please look at the new Default Config and Default VoucherCodes.yml on the main page to see what they now look like. I recommend either deleting your config.yml and start fresh. Or backup your config then delete it and then look at the new config and vouchercode.yml and start moving everything to the right spots.