Hi
here in documentation exists filter is used as follow ?exists[property]=<true|false|1|0> while it works with this syntax: ?property[exists]=<true|false|1|0> (tested with latest release).
I don't know which place require changes doc or filter implementation it self.
Most helpful comment
This was fixed this afternoon: https://github.com/api-platform/docs/pull/430.
Thx for the report.