Cerberus FTP Server is a perpetual license and will continue to work with your current version of the software. Without a valid service agreement, however, you will not have access to technical support nor will you be able to update to any major versions released after your expiry date.
Should you need technical support or a software update moving forward, you will need to contact us to reinstate your service agreement and will potentially incur any associated back fees.
More about back fees here.
Request a quote here.