I'd like to have my slave Postgres DB, which is is hosted on Heroku, replicate from a master DB on my laptop. Is this possible? With version 9.6 or 9.4
I read the question: Follow external database from Heroku but it was for version 9.1
If you speak of streaming replication, then it is not possible and will never be I think. Heroku shares DATABASE - not cluster and streaming replication would require the whole cluster and REPLICATION role access.