Hi Manuel
The problem is not in Dédalo code, it's in the MariaDB or MySQL configuration, normally 𝕊 character or others like that are in UTF8 extension and MariaDB or MySQL don't accept it by default.
If your MariaDB or MySQL has the table or the field in utf8mb3_unicode_ci try to change it to utf8mb4_unicode_ci.
Something like:
ALTER TABLE `publications`
CHANGE `transcription` `transcription` mediumtext COLLATE 'utf8mb4_unicode_ci'
utf8mb3_unicode_ci has the map of used characters in languages, but it doesn't has the full character map, so you can use utf8mb4_unicode_ci when you want publish special characters.
Best
