RowVersion implementation on Entity Framework for PostgreSQL

I am using Entity Framework 6 with PostgreSQL. I have an entity in which I want to prevent concurrency issues, following this documentation I added a RowVersion property with [Timestamp] attribute, however after saving changes to the entity the column RowVersion value stays the same in the database.

    [Timestamp]
    public byte[] RowVersion { get; set; }

Am I missing something or is there another way to handle it in PostgreSQL?

/// <summary>
/// Meant to validate concurrency en database update
/// This column is updates itself in database and only works in postgresql
/// </summary>
[ConcurrencyCheck]
[DatabaseGenerated(DatabaseGeneratedOption.Computed)]
//[NotMapped]
public string xmin { get; set; }

Had to add [NotMapped] attribute just for the column not to be added in the migration, commented it after database-update.