Database structure and emoticon problems due to collation // utf8 vs utf8mb4

Mautic 4.4.10

I have a client with a pretty long living Mautic Installation. Thus it experienced a lot of updates and upgrades in the past with all related troubles in the history of mautic.

When he received forms with emoticons and also copied rich text in lead notes with emoticons, Mautic crashed frequently. And yes, I checked the tables and found out, that lead_notes and also most of the forms use “utf8_unicode_ci” instead of something like “utf8mb4_unicode_ci”.

Before messing around with the database scheme - is there a reference how it should be? As its a most up-to-date version, how comes the database scheme its not up to date?

I compared with my own installation and found our, that lead_notes is also not ready for emoticons. How can I check the current definition? Install a new Mautic from scratch? Or is there some documentation or file I can look up in github?