What's the latest date of monthly social security downsizing?

15 days. Every month1~ 5th is the time for social security system maintenance, so you can apply for social security relief from 5th to15th. Because social security needs to be paid on the 20th of each month, it is necessary to complete the social security relief work before the 20th, and submit the application for social security relief before 15, so you can apply at 15 at the latest.