PHP 8.0 Compatibility
PHP 8.0.0 is scheduled for release Nov 26, 2020.
Backward incompatible changes are listed at https://github.com/php/php-src/blob/php-8.0.0RC5/UPGRADING#L20 for 8.0.0RC5. As one would expect for a major version, it is a long list.
To upload designs, you'll need to enable LFS and have admin enable hashed storage. More information