Substituting PostGres for MS-SQL

How hard would it be to substitute PostGreSQL for MS-SQL? I currently have a Mirror-Replica SQL Server setup, and I’d like to use that if possible.

We are deeply coupled with PostgreSQL, so it’s easier to use another forum software that works with the MSSQL.

That or outsourcing the hosting of either the PostgreSQL part to a service with HA (like AWS RDS) and going all the way and using a hosted service for Discourse :wink: