Do dwp send out decision letters first class?

Hi apologies, I have asked this question on a couple of other threads but I thought if there was anyone around who knows they might catch this thread title in the last 30 minutes til the forum is closed for Xmas! So worth a shot.

So yes,

do the dwp send out decision letters by first class post?

and if anybody knows this one too

if atos write to you with an appointment for a medical is that sent out first class?

Many thanks

Also, Best wishes all for Christmas and the New Year

I don't know whether they send them by first class post but someone I know has just had an acknowledgement of an AA application so fast that if it wasn't sent first class, Royal Mail was being exceedingly kind.

However, whatever postage they use, some of our members do seem to wait a long time for decision letters and some decision letters just seem to disappear into the system somewhere never to appear through the claimant's letter box.