Rewrite code for Automapper v5.0 to v4.0 - automapper

Question

Automapper v4.0 was very straight forward to use within a method, can someone help rewrite this for v5.0 please (specifically the Mapper code):
public IEnumerable<NotificationDto> GetNewNotifications()
{
var userId = User.Identity.GetUserId();
var notifications = _context.UserNotifications
.Where(un => un.UserId == userId && !un.IsRead)
.Select(un => un.Notification)
.Include(n => n.Gig.Artist)
.ToList();
Mapper.CreateMap<ApplicationUser, UserDto>();
Mapper.CreateMap<Gig, GigDto>();
Mapper.CreateMap<Notification, NotificationDto>();
return notifications.Select(Mapper.Map<Notification, NotificationDto>);
}
UPDATE:
It seems that EF Core doesn't project what AutoMapper is mapping with:
return notifications.Select(Mapper.Map<Notification, NotificationDto>);
But I do get results in Postman with the following code:
return notifications.Select(n => new NotificationDto()
{
DateTime = n.DateTime,
Gig = new GigDto()
{
Artist = new UserDto()
{
Id = n.Gig.Artist.Id,
Name = n.Gig.Artist.Name
},
DateTime = n.Gig.DateTime,
Id = n.Gig.Id,
IsCancelled = n.Gig.IsCancelled,
Venue = n.Gig.Venue
},
OriginalVenue = n.OriginalVenue,
OriginalDateTime = n.OriginalDateTime,
Type = n.Type
});

Answer 1

If you want to keep using static instance - the only change is in mapper initialization:
Mapper.Initialize(cfg =>
{
cfg.CreateMap<ApplicationUser, UserDto>();
cfg.CreateMap<Gig, GigDto>();
cfg.CreateMap<Notification, NotificationDto>();
});
Also you should run this code only once per AppDomain (somewhere on startup for example) and not every time you calling GetNewNotifications.