From MySQL 8.0, utf8mb4 is the default character set, and the default collation for utf8mb4 is utf8mb4_0900_ai_ci. MySQL 8.0 is also coming with a whole new set of Unicode collations for the utf8mb4 character set. This will allow use of the complete Unicode 9.0.0 character set in MySQL, and for new applications this is great news.
MySQL Server Blog – https://mysqlserverteam.com/mysql-8-0-collations-migrating-from-older-collations/
Manually set MySQL to support unicode characters was required in the past, but it’s this is no more the case for MySQL 8.0. Unicode is supported by default.
And also “utf8” will refer to “utf8mb3” which is also depreciated. Setting up MySQL 8.0 to use “utf8” (utf8mb3) will cause some unpredictable unwanted behavior, and in some rare cases it could cause the MySQL server to corrupt.
For sources and further readings, you may refers the following:
https://githubmemory.com/repo/Homebrew/homebrew-core/issues/77805
https://mysqlserverteam.com/mysql-8-0-collations-migrating-from-older-collations/
https://mysqlserverteam.com/new-defaults-in-mysql-8-0/
Convert Database Default Character Set to UTF8
By executing the following query:
ALTER DATABASE database_name CHARACTER SET utf8 COLLATE utf8_general_ci;