
That's admittedly not a long time, but it does explain this particular issue that users seem to have. In that, you can upgrade your license and the product version for up to six months following your purchase. "Our program versions are updated regularly and your serial number purchased is valid for the version available for download at that time, and new releases for six months after." When you buy an NCH Software license, you are purchasing a license only for that specific product version:

You can find numerous forum posts wondering why a particular piece of software refuses to accept a paid-for license after an update. One common complaint against NCH Software is that their licenses seem to expire when software versions change. NCH Software sells licenses for its products. WavePad contains optional in-app purchases and subscriptions.When that period ends, you have two choices: pay for a license to continue using the full version, or fall back to a restricted-but-functional free version.

You can also add audio effects including echo, amplify, and noise reduction. You can edit audio files with tools like cut, copy, paste. With WavePad you can edit and record music, voice, and other audio recordings. WavePad Music and Audio Editor is a full-featured professional audio and music editor.
