In the US I would say it's not safe, at least not entirely. That's communication with your prior employer usually from the email address they provided.As long as you're complying with your contractual notice period you're all good. This letter accepts an employee's resignation, noting their last day will be after serving out their required notice period according to their contract. The employee should have stopped work at the end of the notice period and asked for his dues and relieving letter. Kindly assist in training your replacement to ensure a smooth transition. It provides details about the employee's notice period, return of company property, and full and final settlement. Template for an employer to acknowledge an employee's resignation.