InterSystems has been using a two-stream release cadence with InterSystems IRIS since 2018 (see the original announcement from when we started). We provide:
- Continuous delivery (CD) releases — these releases provide access to new features quickly and are ideal for developing and deploying applications that are continuously being updated and can take immediate advantage of new features.
- Extended maintenance (EM) releases — these releases are less frequent than the continuous delivery releases but provide the increased stability of maintenance releases. They are ideal for large enterprise applications where the ease of getting fixes in maintenance releases is more important than getting early access to new features.
We've had very positive feedback about this approach, and people have started referring to the "slow train" and the "fast train". EM releases are the “slow train” preferred by customers and partners that have large on-prem customer bases. CD releases are the “fast train” preferred by customers and partners that are looking for the latest and greatest features.
Many other software vendors are now using this two-stream approach, typically labeling their “slow train” LTS, which stands for Long Term Support. InterSystems' approach to support is very customer-centric; we support customers on any release for as long as they are running it. Hence, we use the Extended Maintenance (EM) terminology.
Our release cadence has evolved as we've grown. Initially, EM releases were in kit form and CD releases were in container form. In 2020, as the popularity of containers grew, we included both kits and containers with EM releases. As a result, EM releases are the ".1" releases each year, and CD releases are ".2", ".3" etc.
With our 2021.2 release we evolved our cadence a bit more:
- CD releases are now available in kit form as well as containers.
- We added HealthShare Health Connect into these release trains alongside InterSystems IRIS and InterSystems IRIS for Health.
We did this because of customer demand. Even though over 70% of developers now use InterSystems IRIS in containers, those that develop directly on MacOS and Windows wanted access to the fast train. Production deployments on CD releases are becoming more common as well, and some customers are less familiar with running with containers in production. Health Connect customers wanted access to frequent new features.
Restrictions on CD Releases
Even though we now provide CD releases in kit form, they are still different from EM releases. CD releases are the "fast train" and are meant for customers to quickly and easily move to the latest and greatest. They have some restrictions:
- There are no maintenance updates or SV updates to CD releases. There are no adhocs on CD releases. Instead, you move to the next CD release, which has all the defect fixes and security updates included. (Note that we may make exceptions to this if warranted - for example we provided a 2021.2.1 update - but these are rare).
- We do not support in-place conversions from Caché or Ensemble to CD releases. Instead, you move to the newest EM release. Customers and Partners who built applications on our previous generation products - Caché and Ensemble - are best served on the "slow train" because it matches the rhythm they are used to.
- Upgrade paths from CD releases are limited to:
- the next CD release (for example, 2020.2→2020.3)
- the next major EM release or a maintenance version of that year (2020.2→2021.1, 2020.3→2022.1, 2020.3->2021.1.1)
These restrictions aren't new, but customers using CD releases in the past were simply replacing containers. We simply didn't run into any situations where customers needed anything else. I did a session at our Virtual Summit 2020 about the InterSystems Product Lifecycle and the feedback I got was that the two-stream approach was working well and the restrictions on CD releases were natural.
Now that we have introduced CD releases in kit form, I wanted to remind folks of how CD releases and EM releases worked. If you use 2021.2 in kit form, you should expect to upgrade to 2022.1. From there you'll be able to continue on the "fast train" or switch to the "slow train" with no extra effort.
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