Thanks for your question and welcome to the Optimus Community Forum!
To answer your question, although Rithmic does support historical data back to the creation of each particular contract, I do not believe you will be able to access this on Sierra Chart with a demo account.
To my knowledge, Sierra Chart + Rithmic supports historical intraday data depending on which Sierra package you subscribe to. For Sierra Chart package 3, 1 Second historical Intraday data is provided. For Package 5 users, tick by tick historical Intraday data is provided. These are for current futures contracts only.
That being said, for longer-term historical Intraday data and for expired futures contracts, Sierra Chart recommends that their users subscribe to the Sierra Chart historical data service. This seems to also be needed for historical daily data as well.
If it is not too much of a hassle, we suggest opening up a new topic if you have follow up questions about backtesting options
Once again, thanks for your question and welcome to the Optimus Community! We hope you found this helpful.
Optimus Futures Support