using old ember data code in ember-cli

I have old ember-data code (revision 14) that I forked and made my own that I want to use with with the latest ember and ember-cli.

Our application code relies heavily on our bastardised version of ember-data and we don't have the budget (or the will) to re-write latest ember-data or get involved with whatever jsonapi is or will be.

How can I work with the old ember-data and latest ember-data considering that the old ember-data relies on a global Ember object?