Ask HN: Should I offer an OSS version?

I sell a WordPress template online that does quite well. The problem is that someone released an older version into the wild and now it's available for free.

I've often thought about releasing a free version in the repo with no customization ability but I'd hate for my sales to suffer.

Has anyone out there decided one way then switched to the other and regretted it? Or switched and had a great experience?