mIRC sales are obviously declining. Author wants to continue supporting it, but the business model no longer works. The options now are:
1) Shut it all down. Author takes a job somewhere else. Product lifetime ends. Lifetime agreement honored.
2) Be honest, admit lifetime agreement isn't workable going forward, and come up with new license terms. Doesn't match the letter of the original license, but project gets to continue and author can continue working on it.
3) Create an "mIRC 2.0" out of nowhere that isn't any different than an incremental update, but gets presented as an all-new product. This is functionally equivalent to #2, but also adheres to the letter of the original agreement.
I don't consider "author forced to work on product in perpetuity at a loss" an option, so I didn't list it here. I prefer admitting that the business model needs to change over shutting down the product or doing name-only new product launches to get around lifetime licenses.