The version number of the database engine to upgrade to. Changing this parameter results in an outage and the change is applied during the
next maintenance window unless the ApplyImmediately parameter is set to true for this request. For major version upgrades, if
a non-default DB parameter group is currently in use, a new DB parameter group in the DB parameter group family for the new engine version
must be specified. The new DB parameter group can be the default for that DB parameter group family. Example: 5.1.42

C# |
public string EngineVersion { get; set; }