Aligning Our Numbers: Kokkos Adopts Semantic Versioning with v5.0

TL;DR: Starting with the Kokkos 5.x series, we’re officially aligning with Semantic Versioning (SemVer) 2.0.0. This means our patch versions will now look like 5.X.Y instead of 5.X.0Y, getting rid of that leading zero that wasn’t quite SemVer-compliant

For years, the Kokkos team has strived for consistency in our versioning, even when it meant sticking to some unconventional numbering. Since the 2.8.00 release in 2019, you might have noticed our patch versions featured a leading zero (e.g., 4.6.01). This format was an attempt to maintain continuity with earlier practices.

While we maintained this scheme out of a desire for consistency and concern for potentially breaking downstream scripts, it has led to many questions over the years. Frankly, most of us on the development team weren’t fond of it either!

The community’s feedback, combined with our commitment to making Kokkos as user-friendly as possible, has driven this decision. Adopting this aspect of SemVer will provide clearer, more predictable version numbers for you, our users.

Our Versioning Strategy Going Forward

With this alignment, we would like to reiterate how we handle major, minor, and patch releases, ensuring our numbering clearly communicates the nature of changes within Kokkos:

• Major Releases (X.y.z): A bump in the major version (e.g., from 4.y.z to 5.y.z) continues to indicate backward-incompatible changes. In Kokkos, this typically means:

  • Bumping the minimum C++ standard requirement (e.g., C++20 for Kokkos 5.0).
  • Updating minimum compiler and toolchain requirements.
  • Removing features that had been deprecated in previous release series. (You can already test this behavior today by configuring your 4 series build with -DKokkos_ENABLE_DEPRECATED_CODE_4=OFF.)

• Minor Releases (x.Y.z): A bump in the minor version (e.g., from 5.0.z to 5.1.z) signifies new features and/or significant improvements that are backward-compatible with the previous minor versions within the same major series. Your existing code should continue to work.

• Patch Releases (x.y.Z): A bump in the patch version (e.g., from 5.0.0 to 5.0.1) will now strictly indicate backward-compatible bug fixes and minor performance enhancements. This is where you’ll see the direct effect of removing that leading zero, moving from 5.0.01 to 5.0.1, 5.0.2, and so on. These updates are generally safe and recommended for all users.

We believe this move, while seemingly small, significantly enhances clarity and adheres to a widely recognized industry standard. This change is part of our ongoing effort to make Kokkos the most robust and user-friendly performance portability ecosystem for the HPC community.

We’re excited about Kokkos 5.0 and the future it brings, both in terms of features and clarity. As always, we encourage you to read the detailed release notes for every update.

Stay tuned for more updates on Kokkos 5.0!