what is the last date of Form Trans 1?

we have not submitted Trans1 yet. we haven't adjusted opening input credit for Jun 17 as of now. please confirm me that what's s last date for trans 1? is it 31 Oct only or we have to submit it before 28 September at once and file a revised trans 1 till 31 October ? is it mandatory to submit it before 28 sep first or we can directly submit it till 31 Oct? Please clear this confusion.