LocalStack Switches to Calendar Versioning
Starting with the March 2026 release, all LocalStack products follow a new YYYY.MM.patch version format. Here's what's changing and what it means for you.
Introduction
With the March 2026 release, LocalStack is switching from semantic versioning to calendar versioning. Instead of version numbers like 4.5.0, you’ll now see 2026.03.0.
This post covers the new format, which products are affected, and what (if anything) you need to do.
The new version format
LocalStack versions now follow this scheme:
YYYY.MM.patch
- YYYY is the full four-digit year (e.g., 2026).
- MM is the two-digit month (01 through 12).
- patch is a number starting from 0 that increments with each fix released within a given month.
So the March 2026 release is 2026.03.0. A fix released later that month would be 2026.03.1, then 2026.03.2, and so on. When the April release ships, the version resets to 2026.04.0.
We picked the full four-digit year on purpose. A shorter format like 26.03 looks too much like a traditional major.minor scheme. pip, for example, uses short years like 25.0, and it’s easy to mistake that for a major version. The full year removes that ambiguity.
Why the switch
Two things motivated this change.
The semantic version numbers had stopped carrying useful information. Over the past few major releases, the amount of breaking changes between versions has shrunk. The bump from v3 to v4 didn’t mean the same thing as earlier major version jumps used to. The “major” number wasn’t telling you much anymore.
On top of that, LocalStack ships on a monthly cadence. Calendar versioning makes that cadence visible in the version number itself. When you see 2026.06.0, you know it’s the June 2026 release without having to look anything up. If you’re running 2026.01.3, you can tell exactly how far behind you are just by reading the version string.
Which products are moving
The following LocalStack products adopt calendar versioning starting with the March 2026 release:
- LocalStack for AWS
- LocalStack for Snowflake
- LocalStack for Azure
- LocalStack Desktop
- LocalStack Docker Extension
The LocalStack Toolkit for VSCode, lstk (the new LocalStack CLI experience) and the LocalStack K8S Operator will follow in a later update.
All of these products share the same version number for a given month (e.g., 2026.03.x in March). Patch numbers are tracked independently per product, since each ships fixes on its own schedule.
What this means for you
How you use LocalStack doesn’t change. Auth tokens, Docker images, CI configuration, and all other settings work the same way. The only visible difference is the version number format.
If you pin to version tags
Update your Docker setup or CI pipeline to use the new format. Where you previously pulled something like localstack/localstack:4.5.0, you’ll now pull localstack/localstack:2026.03.0.
Patch releases
For LocalStack for AWS, expect weekly patch releases that include dependency updates and bug fixes. Other products ship patches as needed. Each product manages its own patch counter independently.
The latest tag
Docker images tagged latest continue to point to the most recent release. If you already pull latest, nothing changes on your end.
Get started
The first calendar-versioned release, 2026.03.0, will be available next week. Update your version pins, pull the new image, and you’re good to go.
If you have questions about the switch, reach out on the LocalStack Community Slack, via support, or through your account manager.
