For MySQL, SQLmig allows logical migrations within the same series and between adjacent series in the following chain:
5.0 ↔ 5.1 ↔ 5.5 ↔ 5.6 ↔ 5.7 ↔ 8.0 ↔ 8.4 ↔ 9.7 ↔ 26.7
A direct jump that skips one or more intermediate series is blocked. For example, a direct transfer from 5.7 to 8.4 must be broken down into adjacent steps. Adjacent downgrades remain logical migrations that should be validated with caution, since not all features of a newer version are necessarily available in the older one.