Here’s what progress bar looks like 
: Postgres support for ERPNext · GitHub
Though ToDo list is kinda incomplete / ever-growing as we discover more requirements.
credit:
- This is largely thanks to @cpdeethree (on github) I am just reviewing / resolving issues as I find.
- Also some previous work by @Verequies (github) is reused too.
- Also slow and steady progress of DB-agnosticism achieved through the adoption of query builder in core: [Announcement] Introducing Frappe Query Builder