What is the retrospective impact on the firm if it was not deducting PF on total comp for International workers, post the new SC judgement?

There are many dual citizenship, expats who worked in India for the firm and we were only deducting PF on basic
How to rectify? If we start deducting from Apr19 will that be enough or is there any retrospective action required and till what year?

In the case of expats, the PF qualifying salary is the same as applicable to the other Indian employees. The only difference is that you cannot restrict the contribution to 12% of Rs 15000 but has to contribute it on the entire basic salary and dearness allowance, if available. You can correct it from April and start contributing it on the total basic +DA. This will have to be done with retrospective effect from their joining by paying the arrears with interest and damages.