PHP 8.0 will be released in December 2020
Some sources brought a bit of confusion about PHP 8's release date. It is scheduled for December 2020, not September 2021.
PHP 8.0 Release Date
According to Nikita's post in February 2020 PHP 8.0 will be released in December 2020.
There are some sources indicating the date of September 2021. They are wrong! PHP 8 is scheduled for December 2020.
PHP 8's features
I wrote a list with PHP 8's confirmed features and other plausible RFCs that might get included. You find such list in this post about the state of PHP 8.