OPAM 1.2 was released in 2014. It was four years before opam 2.0 succeeded it, and another three for opam 2.1. The release of opam 2.2 is imminent, and will have arrived just a year after its predecessor. This talk presents features added to opam 2.1 intended to make dealing with multiple versions of opam easier. We see how small additional metadata, both stored in .opam “roots” and also added to opam’s command line provide opam’s developers with the chance to add new features more easily, with confidence that users will be able to upgrade safely.

In presenting this, we’ll also trumpet some of what we think are the amazing new features of opam 2.1 (and 2.2), and why we think you should keenly watch for new releases and upgrade immediately on release!