Apsaradb for RDS provides you with new versions of your database software.
In the vast majority of cases, minor version upgrade are all non-mandatory. Only when you manually restart an ApsaraDB for RDS instance does the system update the database software to the latest compatible version.
In rare cases (such as fatal major bugs and security vulnerabilities),RDS instances (except basic edition it will initiate a mandatory update of the database version during the maintenance period. Such mandatory updates only result in temporary database disconnections, and will not have any adverse impact on the application if the database connection pool is configured properly.
You can use the console or API set the maintenance window of an ApsaraDB RDS MySQL instance to prevent RDS from being forcibly upgraded during peak hours.