Migration refers to an operation where a technical characteristic of your account is changed. For example, a migration to a new version of MySQL.
The migrations available appear in the alwaysdata administration Advanced > Migrations menu. New migrations are added regularly and we bring this information to our clients by e-mail.
Some migrations are optional: you choose whether or not to migrate. Other migrations are mandatory ones: you have a period of time to migrate. Once the deadline is reached, any remaining migrations are done automatically.