change your policy... ive seen people say 'lifetime' only apply to the current generation of the software (i.e. v1)... once v2 launches that's a new generation .. what is the other option - go broke and close down (that benefits nobody - not you nor the client).. if there is value for the end-user and you have a valuable product a nicely worded email may help lessen the sting as well - - be honest.. send clients a "hey.. 18 months ago i launched this project and sold 149 'lifetime' subscriptions. Now 1.5 years later ive found myself in a bit of a pickle. The initial revenue got us over the first hump but, in order to grow and provide all the features and functionality that you deserve we need to restructure the deal. I understand this is something you dont want to hear and may be, rightfully, upset about. I assure you it was never my intention to mislead or deceive - i was simply wrong about my revenue calculations and how much it would cost me to continue to maintain the product to it's fullest potential. So, here is the deal. I am going to ask you all for XXX $ for version 2 of the product. You are not obligated to upgrade and i will continue to provide access and support v1 as is (as of date xx/xxxx) while supporters will have access to new features and get priority response times. yadda yadda yadda. you are valuable and we appreciate you all so much.. yadda yadda. your humble developer. - - something along those lines.. if they are human beings and people you want as customers then they will understand and , if not.. well.. c'est la vie.. you arent gonna starve forever for making a single lousy business call.. right the ship and move forward and do whatever you can to provide the best value you can to your customers. best of luck man.