What kind of complications would I face downgrading from MySQL 8 to MySQL 5?

Let's assume I wanted to downgrade to from MySQL 8 to MySQL 5.7. [I know this isn't supported](https://dev.mysql.com/doc/refman/8.0/en/downgrading.html) , but what kind of complications am I likely to encounter. The docs say, > The only supported alternative is to restore a backup taken ***before*** upgrading. It is therefore imperative that you backup your data ***before*** starting the upgrade process. Let's say I buck the caveat, and dump on 8 and revive on 5.7? What should I expect? [Dumping on 5.x would product comments like](https://dev.mysql.com/doc/refman/8.0/en/extensions-to-ansi.html) /*!40101 SET character_set_client = @saved_cs_client */; These comments are documented as, > If you add a version number after the ! character, the syntax within the comment is executed **only if the MySQL version is greater than or equal to the specified version number**. Are those kind of comments still produced by version 8? If so, what kind of scenarios would they not cover?