HashiCorp has released a 2.1.4 update to Vagrant -- beware that this version changes the order of plugin loading in a way that breaks on MediaWiki-Vagrant's configuration file.

It should be fixable on our end, but for now either stick with the version of Vagrant you have installed, or downgrade back to 2.1.2 if you already updated.

https://phabricator.wikimedia.org/T203289

-- brion