Good news, WriteMapper is a one-time purchase, and doesn't require you to make recurring payments to continue using it.
The one-time purchase includes lifetime use of the feature set for the major version purchased, with minor updates included. Any future major upgrades will be strictly optional, and available at half off what you first paid, even if the official price goes up in the future.
If we release a major new version with new features, it will not invalidate your existing license. You will be able to use it as long as you like, and as long as it’s compatible with your current operating system.