That's the story with the calendar app I use, http://30boxes.com/

I don't think a new feature has been added in about 5 years and it barely seems maintained, there have been a few day-longish episodes of downtime but other than that it works great.

It has all the features I need and am used to, and I don't have to worry about the product constantly changing. In a way it's almost better to use a neglected product.