The first method: search through your e-mail message to if there is an order email from Foxit Software Incorporated or download the software from the download link provided in the e-mail message. To check which version you purchased,do one of the followings: To check the version information of Foxit PhatnomPDF that you are running, open Foxit PDF Editor, go to Help > About Foxit Foxit PDF Editor. If you are not sure which version you are running and which version you purchased, do the followings: To solve the problem, please do the following:Ģ) Download the correct version that matches to the registration key, and install it. The registration key being used is valid for an old version, it cannot be used for current version you are having on your machine. Registration key is invalid for Foxit PhantomPDF.