MySQL supports replication from one release series to the next higher release series. For example, you can replicate from a master running MySQL 5.6 to a slave running MySQL 5.7, from a master running MySQL 5.7 to a slave running MySQL 8.0, and so on. However, you might encounter difficulties when replicating from an older master to a newer slave if the master uses statements or relies on behavior no longer supported in the version of MySQL used on the slave. For example, foreign key names longer than 64 characters are no longer supported from MySQL 8.0.
The use of more than two MySQL Server versions is not supported in replication setups involving multiple masters, regardless of the number of master or slave MySQL servers. This restriction applies not only to release series, but to version numbers within the same release series as well. For example, if you are using a chained or circular replication setup, you cannot use MySQL 8.0.1, MySQL 8.0.2, and MySQL 8.0.4 concurrently, although you could use any two of these releases together.
It is strongly recommended to use the most recent release available within a given MySQL release series because replication (and other) capabilities are continually being improved. It is also recommended to upgrade masters and slaves that use early releases of a release series of MySQL to GA (production) releases when the latter become available for that release series.
From MySQL 8.0.14, the server version is recorded in the binary
log for each transaction for the server that originally committed
for the server that is the immediate master of the current server
in the replication topology
Replication from newer masters to older slaves might be possible, but is generally not supported. This is due to a number of factors:
Binary log format changes. The binary log format can change between major releases. While we attempt to maintain backward compatibility, this is not always possible. A master might also have optional features enabled that are not understood by older slaves, such as binary log transaction compression, where the resulting compressed transaction payloads cannot be read by a slave at a release before MySQL 8.0.20.
This also has significant implications for upgrading replication servers; see Section 17.5.3, “Upgrading a Replication Setup”, for more information.
For more information about row-based replication, see Section 17.2.1, “Replication Formats”.
SQL incompatibilities. You cannot replicate from a newer master to an older slave using statement-based replication if the statements to be replicated use SQL features available on the master but not on the slave.
However, if both the master and the slave support row-based replication, and there are no data definition statements to be replicated that depend on SQL features found on the master but not on the slave, you can use row-based replication to replicate the effects of data modification statements even if the DDL run on the master is not supported on the slave.
For more information on potential replication issues, see Section 17.5.1, “Replication Features and Issues”.