When will I consider "out of status" after 60-days grace period?

I was recently terminated and now I am applying to transfer my H1b to a new employer (haven’t found it yet). What happens if my new company fills my petition for H1b transfer within the 60-days grace period but I have not received the receipt number? Can I stay in the country?

Will I be out of status if a new employer files a petition but I have not received the receipt number, for example on my day number 60?