I've converted Kanboard to use PostgreSQL for storage instead of SQLite.
This is so it's easier to access data for CliffyPDA. Currently I'm using the Kanboard API, but it takes many requests to get enough data to build a new frontend. There is support for batching requests, but it was still too slow for my liking.
It was surprisingly not as straightforward as exporting from one to the other as each backend (SQLite, MySQL, PostgreSQL) has separate SQL to create them in Kanboard and there's a slight divergence there. Eg: The user table has an extra is_admin field in SQLite that's not in PostgreSQL. Also PostgreSQL stores the database structure version in a table and SQLite stores it elsewhere.
Also fields can be different types, eg: SQLite does not have a boolean field, so it's just stored as a 0/1 there instead of false/true.
So to convert over, I setup an empty Kanboard instance in PostgreSQL, then truncated each table (except the schema_version) and copied in the data from SQLite. Converting and skipping fields where necessary.