I think I’m in a similar situation you’re in. I migrated my schema to use the type system, and now am waiting for v20.07beta, where facet responses are updated (so they work like in v1.1). Dgraph 1.2 and 20.03 uses changed facet responses.
Other than that, the transition should go smoothly. I think there was one dgo change of response type, which should be simple. I tested my logic from v1.1 on v20.03 and it just mostly worked, except for facets.
There was also a change of expand(_*_) queries, as can be seen here.