The California Supreme Court will rule on whether Dynamex, its groundbreaking decision from last year that could upend many gig jobs, can be applied retroactively.

The Ninth Circuit Court of Appeals in May said that Dynamex applies retroactively. But on Monday, the appeals court issued an order withdrawing that previous decision and said it would ask the state Supreme Court to decide whether its own ruling applied retroactively.

Dynamex limits companies’ ability to claim that workers are independent contractors. It says that workers are employees if they are under a company’s control, do work central to its mission and do not have independent enterprises doing that type of work.

The state high court already rejected a previous attempt by the case’s defendant, delivery company Dynamex, to modify the decision to say it was not retroactive, according to Shannon Liss-Riordan, a Boston attorney who represents many plaintiffs suing gig-economy companies to seek employment status.

“I look forward to the Supreme Court taking on this case and definitively putting this retroactivity question to rest,” she said in an email, adding that the original appeals court order was correctly decided.

The California Legislature is now working on a labor-backed bill, AB5, to codify and clarify Dynamex. Uber and Lyft, the most-prominent gig companies, could be forced to reclassify their drivers as employees if AB5 passes, adding to their labor costs and potentially reducing some scheduling flexibility. AB5 passed the Assembly in May and a Senate committee this month. It will be heard by another Senate committee in August before heading to the full Senate floor by September.

Carolyn Said is a San Francisco Chronicle staff writer. Email: csaid@sfchronicle.com Twitter: @csaid