H1B visa extension got approved with past date

[rohit56]

I got H1b visa extension approval on Jun 28 2019, with approval date as 31 December 2018. Visa extension was filed on October 29 , 2018(Normal Processing) .
Employer will be filing a new extension by tomorrow 03 July 2019. So can I stay back here if the extension is filed or do I need to travel immediately ?