What is the correct syntax for a Flyway connection string to SQL Server?

In case anyone's problems, the correct connection string is as follows:

flyway.url=jdbc:jtds:sqlserver://SERVER_INSTANCE_NAME:1433/DB_NAME

It took me some time to realize that, but maybe it will be helpful for someone :)

This one got me, and there was not many answers out there on how to format a connection string with an instance name.

Here's what worked for me:

flyway.url=jdbc:jtds:sqlserver://<host>:<port>/<database>;instance=<instance_name>