In conjunction with this the state has created a Minimum Wage Credit for those small companies (less than 50 full-time equivalent employees) that are moving employees up to $9.25 at the start of the year. FY2020-13, attached, goes over the details but it boils down to this: The state will give employers a credit for the difference between each employee’s old pay rate and the new minimum wage for every employee that was below minimum wage. So employees going from $8.25 to $9.25 will generate a withholding credit of 25% of the difference of $1.00 on their actual earnings each quarter. I presume tipped workers increasing to the new tipped minimum wage also qualify. If you pay more than the minimum wage, you still only get a withholding credit up to the minimum wage.
There are still open questions on this. I don’t know how the Cook Co & City of Chicago minimum wages play into this.
Also at the federal level, the minimum salary to be permitted to be exempt from overtime is increasing from $455 per week (or $23,660 annually) to $684 per week (or $35,568 annually) as of 1/1/20. Employee’s must still meet the duties test to be considered truly exempt from overtime.