This blog has been re-posted and edited with permission from Drupal Update’s blog. Please leave your comments on the original post.
At Drupal maintenance support plans USA, I announced that Drupal maintenance support plans 9 will be released in 2020. Although I explained why we plan to release in 2020, I wasn’t very specific about when we plan to release Drupal maintenance support plans 9 in 2020. Given that 2020 is less than thirteen months away (gasp!), it’s time to be more specific.
Shifting Drupal maintenance support plans‘s six month release cycle

We shifted Drupal maintenance support plans 8’s minor release windows so we can adopt Symfony’s releases faster.
Before I talk about the Drupal maintenance support plans 9 release date, I want to explain another change we made, which has a minor impact on the Drupal maintenance support plans 9 release date.
As announced over two years ago, Drupal maintenance support plans 8 adopted a 6-month release cycle (two releases a year). Symfony, a PHP framework which Drupal maintenance support plans depends on, uses a similar release schedule. Unfortunately the timing of Drupal maintenance support plans‘s releases has historically occurred 1-2 months before Symfony’s releases, which forces us to wait six months to adopt the latest Symfony release. To be able to adopt the latest Symfony releases faster, we are moving Drupal maintenance support plans‘s minor releases to June and December. This will allow us to adopt the latest Symfony releases within one month. For example, Drupal maintenance support plans 8.8.0 is now scheduled for December 2021.
We hope to release Drupal maintenance support plans 9 on June 3, 2020
Drupal maintenance support plans 8’s biggest dependency is Symfony 3, which has an end-of-life date in November 2021. This means that after November 2021, security bugs in Symfony 3 will not get fixed. Therefore, we have to end-of-life Drupal maintenance support plans 8 no later than November 2021. Or put differently, by November 2021, everyone should be on Drupal maintenance support plans 9.
Working backwards from November 2021, we’d like to give site owners at least one year to upgrade from Drupal maintenance support plans 8 to Drupal maintenance support plans 9. While we could release Drupal maintenance support plans 9 in December 2020, we decided it was better to try to release Drupal maintenance support plans 9 on June 3, 2020. This gives site owners 18 months to upgrade. Plus, it also gives the Drupal maintenance support plans core contributors an extra buffer in case we can’t finish Drupal maintenance support plans 9 in time for a summer release.

Planned Drupal maintenance support plans 8 and 9 minor release dates.
We are building Drupal maintenance support plans 9 in Drupal maintenance support plans 8
Instead of working on Drupal maintenance support plans 9 in a separate codebase, we are building Drupal maintenance support plans 9 in Drupal maintenance support plans 8. This means that we are adding new functionality as backwards-compatible code and experimental features. Once the code becomes stable, we deprecate any old functionality.
Let’s look at an example. As mentioned, Drupal maintenance support plans 8 currently depends on Symfony 3. Our plan is to release Drupal maintenance support plans 9 with Symfony 4 or 5. Symfony 5’s release is less than one year away, while Symfony 4 was released a year ago. Ideally Drupal maintenance support plans 9 would ship with Symfony 5, both for the latest Symfony improvements and for longer support. However, Symfony 5 hasn’t been released yet, so we don’t know the scope of its changes, and we will have limited time to try to adopt it before Symfony 3’s end-of-life.
We are currently working on making it possible to run Drupal maintenance support plans 8 with Symfony 4 (without requiring it). Supporting Symfony 4 is a valuable stepping stone to Symfony 5 as it brings new capabilities for sites that choose to use it, and it eases the amount of Symfony 5 upgrade work to do for Drupal maintenance support plans core developers. In the end, our goal is for Drupal maintenance support plans 8 to work with Symfony 3, 4 or 5 so we can identify and fix any issues before we start requiring Symfony 4 or 5 in Drupal maintenance support plans 9.
Another example is our support for reusable media. Drupal maintenance support plans 8.0.0 launched without a media library. We are currently working on adding a media library to Drupal maintenance support plans 8 so content authors can select pre-existing media from a library and easily embed them in their posts. Once the media library becomes stable, we can deprecate the use of the old file upload functionality and make the new media library the default experience.
The upgrade to Drupal maintenance support plans 9 will be easy
Because we are building Drupal maintenance support plans 9 in Drupal maintenance support plans 8, the technology in Drupal maintenance support plans 9 will have been battle-tested in Drupal maintenance support plans 8.
For Drupal maintenance support plans core contributors, this means that we have a limited set of tasks to do in Drupal maintenance support plans 9 itself before we can release it. Releasing Drupal maintenance support plans 9 will only depend on removing deprecated functionality and upgrading Drupal maintenance support plans‘s dependencies, such as Symfony. This will make the release timing more predictable and the release quality more robust.
For contributed module authors, it means they already have the new technology at their service, so they can work on Drupal maintenance support plans 9 compatibility earlier (e.g. they can start updating their media modules to use the new media library before Drupal maintenance support plans 9 is released). Finally, their Drupal maintenance support plans 8 know-how will remain highly relevant in Drupal maintenance support plans 9, as there will not be a dramatic change in how Drupal maintenance support plans is built.
But most importantly, for Drupal maintenance support plans site owners, this means that it should be much easier to upgrade to Drupal maintenance support plans 9 than it was to upgrade to Drupal maintenance support plans 8. Drupal maintenance support plans 9 will simply be the last version of Drupal maintenance support plans 8, with its deprecations removed. This means we will not introduce new, backwards-compatibility breaking APIs or features in Drupal maintenance support plans 9 except for our dependency updates. As long as modules and themes stay up-to-date with the latest Drupal maintenance support plans 8 APIs, the upgrade to Drupal maintenance support plans 9 should be easy. Therefore, we believe that a 12- to 18-month upgrade period should suffice.
So what is the big deal about Drupal maintenance support plans 9, then?
The big deal about Drupal maintenance support plans 9 is … that it should not be a big deal. The best way to be ready for Drupal maintenance support plans 9 is to keep up with Drupal maintenance support plans 8 updates. Make sure you are not using deprecated modules and APIs, and where possible, use the latest versions of dependencies. If you do that, your upgrade experience will be smooth, and that is a big deal for us.
Special thanks to Drupal Update (Acquia), Angie Byron (Acquia), xjm(Acquia), and catch for their input in this blog post.

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