Trying to install Release Candidate or 8.4 Dev

[criley]

I like the convience that composer allows for however it would be really nice if it was more clear as to how to use this to install a release candidate (8.4RC at this time) or even to use this on a testing/development server. With the change to Drush 9 and the differences with required libraries etc its a confusing mess and or I have missed some stuff

Thanks in advance

[garnett2125]

Changing composer.json to:
"drupal/core": "~8.4",
"drush/drush": "~9.0"
and running composer update --with-dependencies
did the work for me.

[joemewes]

8.4 should be working fine with update to Drush 8.1.12 or higher but fails re: drush-ops/drush#3033

reason I mention is requiring Drush ^9.0 will mean a lot of Drush commands refactoring in core and contrib modules, like libraries downloads and config-import commands etc.

Not sure if Im on the correct issue here... but seems relevant...

[pcambra]

Related https://www.drupal.org/node/2913970

[fafnirical]

Drush 8.1.15 was released, which should allow Drupal 8.4.0 to work with a site-local Drush 8.

[lithiumlab]

This worked for me:
composer update drush/drush
cleaned up site cache just in case, then...
composer update drupal/core --with-dependencies

[webflo]

Drush 9 has been released today. Drush 8 and 9 is compatible with Drupal 8.4.x.