Postgres plv8 on Trusty

Trying to move from Precise to Trusty, but I get an error adding the PLV8 extension:

PG::UndefinedFile: ERROR:  could not open extension control file "/usr/share/postgresql/9.5/extension/plv8.control": No such file or directory

when I try to run:

CREATE EXTENSION IF NOT EXISTS plv8;

Is there a way to add this for my build?

The highest version that currently exists in the Ubuntu package repository is 9.3, so you would either need to downgrade Postgres, or build plv8 following the instructions at https://github.com/plv8/plv8#install

Thanks but I’m confused since Precise had plv8 support. I guess circle built it then?