Thanks for reporting this. We’ve had a few other reports of it and we’re preparing a new release to address it.
This warning occurs on PHP 8 servers when you process articles which contain JSON-LD elements with multiple values in the
@type property. In our tests we hadn’t come across any such articles (all of them listed a single value, e.g. ‘NewsArticle’ or ‘BlogPosting’).
The warning only occurs on PHP 8 because type conversion from array to string generated a notice in PHP versions prior to version 8 but produces a warning in PHP 8. Full-Text RSS ignores notices but not warnings.
The updated version deals better with this and shouldn’t trigger a warning or notice any more.
We’ll email once it’s out - planned for a little later today.