We have been using Journey Builder for about 3 years, and some of our existing Journeys are set up to use "Process All Records". However, I remember there used to be an option to "process new records" that enter the data extension to be inserted into the Journey. We recently came across a scenario where we need to only process new records. I have been unable to see this option every time I create the entry source using Data Extension and a schedule or an automation. Has this option been discontinued?
The location of this configuration has changed some in the last couple of years. It is still an option when using a Data Extension entry source connected to an Automation Studio automation.
After you select a data extension and an automation schedule in Journey Builder you should see a screen with options to define the schedule as below.