I only recommend it if you know what you are doing.
You have to change the database field type from utf8 to utf8mb4
Here is an excample of the message table for PMs, you´ll have to change it in other tables too, if the emojis have to work. Forums. comments, etc
gizmodo.com/why-other-people-cant-see-your-emojis-and-how-to-fix-it-1820037259
quote from the article:
These boxes and question marks appear because emoji support on the sender’s device is not the same as emoji support on the device of the recipient.
how are you sending the emoji, by text code or by plugin?
remember that oxwall does not support mobile. They have a mobile version but it is horrible and incomplete, so if you are trying to use the oxwall mobile version there is no support for that yet.
it might help if you take a snapshot or picture of what you are trying to do.