The TECH and LTS streams were designed to allow the Unity devs to rapidly release features while still being able to support a stable version of Unity.
Last week Unity Technologies announced their plans for future releases of the Unity editor. They’ve create a new release schedule that’ll make it easier for developers to try out Unity’s latest features while still giving them the option to stick with a stable version for their ongoing projects. This new schedule consists of two parts, which will be called the TECH and Long-Term-Support streams. Overall, these release streams are pretty straightforward. But, I wanted to cover a few of details that might answer some questions I’ve seen asked by the community since the announcement was made.
Current Release Schedule
Unity currently delivers four feature releases annually, supporting each one with regular bug fixes for an entire year. This model works fine as a starting point, but it doesn’t really scale well. I mean, think about it; depending on the cycle and how many patch versions are released, the developers at Unity could be expected to support up to dozens of versions at a time. That’s a tall order to fill. Plus, having that many supported versions in the wild can lead to tons of confusion in the game dev community. Imagine encountering a bug and having to sift through all the solutions on StackOverflow or Unity Answers looking for one that applies to the version of Unity that you’re currently using. That’s a real headache.
The New Release Schedule
Starting this year, Unity’s new release schedule aims to solve these and many other issues that crop up with the current implementation. Unity will deliver three feature releases every year. One in the Spring, one in the Summer, and one in the Fall. These feature releases will be called “TECH stream releases”, and each one will be supported until the next one goes live. Then, at the end of each year, Unity will deliver a final release, which will be a part of the Long-Term-Support (or LTS) stream. LTS steam releases will be supported for two years after they go live.
As I mentioned before, there will be three TECH stream releases every year. Each TECH stream release will be supported until the next one goes live. During their support period, TECH streams will receive weekly bug fixes, which will be versioned using the current year, the number of TECH releases in that year, and the number of bug fixes released in that particular TECH release. So, the first TECH stream release in Spring of 2018 will be 2018.1.f0. Another detail to note is that the p suffix, which stands for patch, is now being replaced by the f suffix. This is due to the fact that feature releases are tested so thoroughly that Unity is confident that each one will be stable.
LTS stream releases will be delivered once a year, as soon as the first TECH stream of that year goes live. They will receive support for two full years, which will consist of bi-weekly bug fix releases that’ll address crashes, regressions, and issues that would affect projects that are either in development or have already been launched. LTS stream releases will be versioned using the year they were released, the number four, and the number of bug fixes in that release. The first official LTS stream release is version 2017.4.f0, and went live during this year’s GDC, when the announcement for TECH and LTS streams was made.