Is this a thing?

I purchased the full version, not the free version, a couple of years ago, and liked it and it seemed to be accurate within the San Francisco Bay area. Although certainly four bucks is not going to break the bank, I do have issues that when the upgraded, they deactivated my purchased version, requiring me to purchase again if I want the upgrade. Also, since I do not own the current version, will not let me review on the paid version. I understand subscription software, and how it is probably a better model long-term to ensure upgrades and maintenance, but this was not advertised as such, so find it sketchy and unethical bordering on bait and switch to not have disclosed that there would be continued purchases required to use it. I probably used it for a year before it vanished, but I would be incredibly upset if I had purchased it and the next month the new version came out, and deactivated my old version.

Sfpen2010 about Ship Finder Lite, v9.0.0