There are a lot of breaking changes. In terms of API usage, the REST APIs are replacing the JSON RPC methods.
Database tables and views have been also changed.
Notable features/changes:
op_* and vo_* have been removed and replaced with operation_*_table and operation_*_view - See documentations - Each replacing table might have a slightly different structure/data typeshaf_*The API documentation link is also the endpoint for the REST APIs. Every node running HafSQL will also serve that documentation. The APIs are not done yet and more will be added.
The database documentation provides an easy way of searching the columns and the tables. It also includes the new endpoint of the public HafSQL node (hafsql-sql.mahdiyari.info).
The switch to the breaking code will be after the official HAF 1.27.6 release. Until then the old node will work (hopefully). Test your codes and be ready for the official release as this is just a release candidate.
The main repository and the documentations should have all you need for using HafSQL either locally or by the provided public node. I have tried to write only useful information there.
Main repository: https://gitlab.com/mahdiyari/hafsql
Docker hub: https://hub.docker.com/r/mahdiyari/hafsql
I will try to complete the API list as far as I can for the data already present in the database and have public API nodes run and provide HafSQL APIs.
I will probably write another post after the above is done and discuss what comes next.