SQL server data source with ApplicationIntent = ReadOnly

For a DataSource on the Admin page that is a Microsoft SQL connection, I need to set the ApplicationIntent to ReadOnly.

We are running on an old CF10 version (upgrade scheduled for later this year), so is the only way to do this is by entering the Connection String value in the DataSource advanced options?

(and of course only selecting the Read tick boxes below it, turning off the update, insert, etc)

(and if it is, any typical examples would be really useful).