How to switch to the new FB API version?

Question

Python

Good day.
There was a problem related to the fact that they did not switch to the new version of graph api in a timely manner and postponed the transition until the last one.
The essence of the problem is that old users (those who were registered before the introduction of the new api graph) are identified by the canonical ID. New - by scope.
When updating the api version on our server (corrected links for the api graph, updated js library for the client, updated python library for the server). When authorizing old users, a new profile is created with a new scope ID, the old profile (from canonical) remains a dead weight, along with its data and progress.
The essence of the question is how to connect the old canonical id with the new scope in order to be able to at least make synchronization?