The employee is expected to know difference between Jan16 and May06.
The employee should not have mentioned in Resume, employment application also that he worked in last company till May16 if he in fact worked till Jan16.
The employee has the option of regretting to last employer (and current employer if current employer is also acting in the matter) and close the matter without last and current lodging any complaint and case against employee.
And assure that he/she shall not indulge in such act in future.
If this can be resolved verbally, nothing like it.
The employee could have rather pursued to get relieving letter, properly, without committing any such transgression.