Heroku's Aspen stack is the product that launched our company and inspired a new class of cloud services. After much deliberation and careful thought, we have decided to sunset the Aspen stack by Thursday, November 22nd. We ask application owners still using Aspen to migrate to Cedar.

Since Aspen's launch over four years ago, Rails has seen the introduction of Bundler for dependency management, the asset pipeline, and a major framework re-write. Heroku has also grown, and with the introduction of the Cedar stack, we have moved beyond our humble origins and have become a true polyglot platform.

The Aspen stack was a prototype that served as a living vision of what a platform that...

Software erosion is what happens to your app without your knowledge or consent: it was working at one point, and then doesn't work anymore. When this happens you have to invest energy diagnosing and resolving the problem. Over a year ago Heroku's CTO, Adam Wiggins, first wrote about erosion-resistance on Heroku. Part of erosion-resistance is communication, and knowing what to expect moving into the future. This post will clarify what we mean by erosion-resistance, and help you understand what to expect when one of our features is deprecated or is sunset.

Erosion Resistance

Erosion-resistance means that your apps are protected against accidental or unannounced changes because...