According to SC in their support forums:
Effective towards the end of 2020, most likely in December 2020, newer versions of Sierra Chart will no longer support connectivity to Rithmic.
Depending upon our schedule with replacement services, this date can be moved earlier in time. But not likely to be earlier than June 2020.
What are our options when this takes place? I want to continue to use Sierra Chart, but have no interest in paying for separate connectivity to data feeds.