Send Email using MailKit in ASP.Net

This is the code behind

Imports System.Net
Imports System.Net.Mail
Imports System.Data
Imports System.Threading.Tasks
Imports System.Data.SqlClient

Partial Class VB
    Inherits System.Web.UI.Page
    Protected Sub SendBulkEmail(sender As Object, e As EventArgs)
        Dim constr As String = ConfigurationManager.ConnectionStrings("ConnectionString").ConnectionString
        Dim con As SqlConnection = New SqlConnection(constr)
        Dim cmd As SqlCommand = New SqlCommand("SELECT Name, EmailAddress FROM Email", con)
        Dim da As SqlDataAdapter = New SqlDataAdapter(cmd)
        Dim dtCustomers As DataTable = New DataTable()
        da.Fill(dtCustomers)
        Dim subject As String = Request.Form("Text1")
        Dim body As String = Request.Form("TextArea1") & "<br /><br />To opt-out "
        body += "<a href = '" & Request.Url.AbsoluteUri.Replace("VB.aspx", "optout.asp?Email=" & dtCustomers.Rows(0)("DEREmailAddress").ToString()) & "'>click here</a>."

    Parallel.ForEach(dtCustomers.AsEnumerable(), _
                     Function(row)
                         Return SendEmail(row("EmailAddress").ToString(), subject, String.Format(body, row("Name")))
                     End Function)
    End Sub
    Private Function SendEmail(recipient As String, subject As String, body As String) As Boolean
        Dim mm As New MailMessage("someone@Somewhere.com", recipient)
        mm.Subject = subject
        mm.Body = body
        mm.IsBodyHtml = True
        Dim smtp As New SmtpClient()
        smtp.Host = "Somewhere.com"
        smtp.EnableSsl = False
        Dim NetworkCred As New NetworkCredential()
        NetworkCred.UserName = ""
        NetworkCred.Password = ""
        smtp.UseDefaultCredentials = True
        smtp.Credentials = NetworkCred
        smtp.Port = 25
        smtp.Send(mm)
        Return True
    End Function
End Class

I was doing some research and and found this: https://stackoverflow.com/questions/43517434/is-system-net-mail-smtpclient-obsolete-in-4-7/43517528 and a couple other links explaining the same thing. 

SMTPClient is obselete and isn't being recommended to be used in new applications. Even if this is going to be a short use app, I hate to be learning and or using something that is obselete. On the other hand, I'm not finding ready made software/app whether it be free or cost some $$. I also am not finding anything similar using MailKit. 

Has anyone used it and could it be used here instead of the smtpclient?