Drupal 8 will require PHP 7 starting March 6, 2019 (one year from now); PHP 7.1+ recommended

Drupal 8 will require PHP 7 starting March 6, 2019. Drupal 8 users who are running Drupal 8 on PHP 5.5 or PHP 5.6 should begin planning to upgrade their PHP version to 7.0 or higher (PHP 7.1+ is recommended). Drupal 8.6 will be the final Drupal 8 version to support PHP 5, and will reach end-of-life on March 6, 2019, when Drupal 8.7.0 is released. (If 8.7.0 is released before March 6, 2019, the release number for the end-of-life will be updated accordingly, but the end-of-life date will remain the same.)

When planning a PHP version to upgrade, consider that PHP 7.2 was released on November 30, 2017 and will remain supported longer than older PHP 7 versions.

Why is support being dropped for PHP 5.5 and 5.6?

• PHP 5.5 has already reached official end-of-life in 2016. Following that, a growing number of the PHP libraries used by Drupal 8 have also started to discontinue support for PHP 5.5.
• PHP 5.6 stopped receiving active support from PHP maintainers in January 2017. This means that it is no longer receiving bugfixes, even for some very serious bugs that impact Drupal development.
• PHP 5.6 is the final PHP 5 version, so the PHP maintainers are providing two years of security fixes for PHP 5.6 beyond its active support, through December 2018. This is a few months after Drupal 8.6's scheduled release and well before Drupal 8.7 would be released.
• Drupal 8's automated tests require the PHPUnit library, which will drop support for PHP 5.6 in February 2018. Several other third-party dependencies are also dropping PHP 5.6 support in their latest versions.
• To minimize disruption for both Drupal users and Drupal developers, Drupal 8's support of PHP 5.5 and PHP 5.6 will end at the same time.

We understand that upgrading from PHP 5 to PHP 7 may require time to plan and deploy. We suggest upgrading to PHP 7 in 2018 (rather than waiting for Drupal 8.7.0’s release).

What if I'm using a hosting service that doesn't offer PHP 7?

A majority of PHP hosting providers already offer PHP 7. If you're using one that doesn't, we suggest asking that provider when they will make it available, and if it's not until after March 2019, leave a comment on our tracking issue linking to that hosting provider, so that we can better understand the outliers, and perhaps offer some help.

What if I'm at an organization that maintains its own hosting, and we're using Ubuntu 14.04, which bundles PHP 5.5?

You have a few options if you are using Ubuntu 14.04:

1. The preferred option is to plan an upgrade to Ubuntu 18.04 (to be released on April 2018, 2018). This version will be the most future-compatible.
2. Another option is to upgrade Ubuntu 16.04, which is available now. You may need to upgrade Ubuntu again in a couple years if you choose to upgrade to 16.04 now.
3. Finally, you can choose to upgrade to a separate build of PHP. Ondřej Surý provides a widely used PPA for doing this.

When will Drupal 8 drop support for PHP 7.0?

Support for PHP 7.0 will continue until at least March 6, 2019. We do not yet know whether Drupal 8's PHP 7.0 support will continue past that date, but we will post another announcement as soon as the end of PHP 7.0 support has been scheduled. We recommend you update to PHP 7.1 or higher since those versions will be supported longer.

How does this affect Drupal 8 core development?

Backported fixes account for about 80% of all changes and must continue to work on PHP 5.5 and 5.6 throughout Drupal 8.6.x's support cycle. For this reason, no PHP 7-only changes will be made until the 8.8.x branch is opened in early 2019 (or 8.9.x if 8.8.0 is released in 2018). Once 8.8.x is opened, the library dependencies in that branch can be updated to versions that have a PHP 7.0 requirement, and the Drupal code itself in that branch can begin relying on PHP 7 features. (Drupal 8 release cycle information)

Currently PHPUnit 6 is only used by automated test suite when it is running on PHP 7.2. PHPUnit 4 is used on PHP 5-7.1. In Drupal 8.8.x, support for PHPUnit 4 will be removed. At some point before 8.8.x it is likely that PHP 7.0 and 7.1 will use PHPUnit 6.

Does this affect Drupal 7?

No. Drupal 7 remains compatible with PHP 5.2.4 and higher. A separate announcement will be issued if and when that changes.