Npm is available on your VPS, so you can install latest Yarn in your home directory as well with npm install yarn. Some WordPress themes rely on Yarn to aid in the asset building process.

For our policy regarding extra packages:

1. If it is a package that exists in the standard Ubuntu repositories, we’ll consider it.
2. If the package in question is a tool such as emacs, we’ll add it without concern.
3. If it is something needed to assist you in maintaining or building code such as grunt, npm, or composer, that’s perfectly acceptable as well.
4. Any items outside those specified above must be reviewed before approval. We don’t generally allow running other services outside of the PressARMOR™ security-hardened environment.
   

Check out our fully-managed dedicated VPS Hosting Plans designed exclusively for high performing WordPress.