At GDC, we announced our new plans for Unity releases, which include what will be known as the TECH stream and the Long-Term Support stream (LTS). The TECH stream will consist of three major releases a year with new features and functionality. The LTS stream will be the last TECH stream release of each year and will roll over to the following year. This blog post explains the idea behind the new release system followed by answers to Frequently Asked Questions.

The TECH & LTS streams represent a major shift from the current approach of supporting each of the releases for a year. From now on:

Support for each respective TECH release will end when the following one goes live.

LTS releases will be supported for two years.

Other aspects of our approach to releases will also change:

From four to three releases: Instead of four feature releases, we are going to ship three TECH stream releases per year.

First release in spring: Each year, a TECH stream will begin in the spring, this year starting with 2018.1. This will be followed by summer and fall releases.

Frequency of bug fixes: Whereas the TECH stream will receive a weekly release with bug fixes, the LTS stream will receive regular bug fixes every other week.

From patches to updates: We are dropping the .p# suffix for our weekly patches because, due to our improved testing of these releases, we believe they will be suitable for everyone.

How the new streams will work in practice

The first LTS release will be 2017.4, which is simply the latest 2017.3 updated release. The change in version number signifies that it is the beginning of the new LTS cycle. So, xxxx.1, .xxxx.2 & xxxx.3 are TECH releases and xxxx.4 is the LTS release.

The regular updates on both TECH and LTS streams will have continuous version numbering. For example, 2017.4.0 will be followed by 2017.4.1, 2017.4.2, 2017.4.3, and so on.

The chart below shows an example of how the streams will work, with the blue boxes representing the TECH streams and the green boxes representing the beginning of the LTS streams.

The new TECH and LTS streams

FAQs

Why is Unity changing the current approach?

Splitting releases into the TECH and LTS streams will enable us to offer you the maximum value according to your needs. Depending on where you are in your development cycle, you may want either to try out new features (TECH release) or only to get bug fixes in the version you are using for a longer period without adding new features (LTS).

For those of you starting or in the middle of production, or just looking for the latest features, we offer the latest version of Unity with all the new features in the form of the TECH stream. For those of you who are nearing the end of production or are operating a live game, we have the LTS stream in which only bug fixes are added.

What are the main ideas behind these changes?

With only two streams to support and with LTS strictly controlled for bug fixes, we can focus on supporting you more effectively and efficiently. By supplying one stream focusing on new technology and another providing long-term support for a version with matured features, we expect to cover the majority of different users’ needs. However, we will continue to listen to your feedback and improve the process as we go.

What is the connection between the TECH and LTS streams?

When a new TECH stream goes live (for example version 2019.1), the previous version (in this example, 2018.3) will become an LTS with a new version number, 2018.4.



How frequently do the releases from a TECH stream get updated?

TECH streams will be updated with weekly releases. Most of the development efforts will be focused on stabilizing and improving the TECH releases as soon as possible.

How will future requirements/integrations be dealt with?

The objective is to support the LTS stream for two full years for customers who choose to stay on it. Any future changes requiring support will be added on a case-by-case basis.



Why did you bump the version number to YEAR.4?

We wanted to have a clear point at which the two-year support schedule begins. Also, we wanted to begin a new LTS stream at around the same time the new TECH stream begins.

What does LTS stand for?

LTS stands for Long-Term Support.

How long will an LTS stream be supported?

Each LTS release will be supported for two full years from the time it is announced.

Who is the LTS stream intended for?

The LTS stream is for users who wish to continue to develop and ship their games/content and stay on a stable version for an extended period.

Who is the TECH stream intended for?

The TECH stream is for anyone who wants to use the latest features and those who want to be up-to-date with the latest Unity is offering.

What are the main issues that an LTS stream will address?

The LTS version will not have any new features, API changes or improvements. It will address crashes, regressions, and issues that affect the wider community, console SDK/XDK, or any major changes that would prevent a large section of users from shipping their game.

Will there be updates for both the TECH and LTS streams?

Yes.

We will continue to offer weekly updates for the TECH stream. However the updates for the current TECH stream will stop when the next one is released. For example, when 2018.2 is released, weekly updates for 2018.1 will stop, and when 2018.3 goes live, support for 2018.2 will end.

The LTS updates will be less frequent with one every other week. The updates will continue for two years with the version numbers going as: YEAR.4.1, YEAR.4.2, …, YEAR.4.24, for example.

Will there be any version number changes to updates for the TECH and LTS streams?

All updates for both TECH and LTS streams will have .f suffixes as they are not patches but fully tested updates recommended for all.

Why do you call them updates and not patches ?

The .p suffix used for patches has been replaced by the .f suffix because these regular updates are released with extended testing. This is due to the change in our release-testing process. The dedicated Sustained Engineering QA team has started doing extended tests in addition to verifying each of the bug fixes in patch releases some time ago. This extended testing, known as Release Acceptance Testing, is performed using a whole host of manual tests done across various areas. So, there is no need to do both patches and wrap-up of public releases any longer.

What happens to the legacy versions, 5.6, 2017.1 & 2017.2 ?

As mentioned, 2017.3 has become 2017.4 marking the beginning of 2017-LTS. As promised, all legacy versions will be supported with patches, with .p suffixes for a year from their releases.