There use to be a plus and minus sign next to the episode number under your "currently watching" list to update when you finished another episode.  Now I can't keep track of all the episodes I have watched.

The minus and plus are still there but apparently can't be used. If you press edit you can add watched episodes. But then when that extra box closes you'll have to update you watch list to be able to see that the episode has been added. A lot more complicated than before. Hope it gets fixed. 

+/- sign is still there and working. Also, update will reflect the value on the dramalist.

Maybe she's talking about on the mobile version?  But even there I see the + sign and i just tried it and it works. 

I was using my tablet. It looks like the normal webpage and not like when I use my mobile.