Ivan, right now this is a major PITA. Right after your response I headed over to the livechat.
It took less than 1 minute for a reply but we are still fiddling around about redeeming the coupons and it just won't work.
For existing users there seems to be no field to redeem the coupon.
Logging out and clicking the /appsumo/ link let's me input a code, but after that I can only SIGN UP, not SIGN IN to have the code applied to my account.
And when I'm logged in there is no way to get to any field where I can redeem the coupon.
We are closing in on one hour I am looking for a solution with your support that didn't really care to actually read what I wrote. Because she only gave me solutions that I had already adressed in my initial message.
We're going in circles. Please have a tech guy input the code field for existing users, it's getting way more frustrating than anticipated.
Of course I understand that a deal like this always comes with some bumps and roadblocks. ;)

Okay, support's solution looks like this:

"I’m sorry for this issue. Please, create a new account to use AppSumo code"

That's why I was asking if it is only for new accounts. But nowhere in the copy says that it's only for new ones.
I'd rather have it work for my existing account, please advise if I should wait.

Does you issue is fixed?

Hey Ivan,
no, it's not.
That's why I was asking if you guys actually make the coupon field for existing customers available or if I have to register with a new email.
If so then the copy of this deal would need to be adapted to reflect that only new users can take this offer.

@schnitzel we can manually update your existing account to AppSumo plan.

So, you can use two ways to redeem codes:

1. Create a new account.
2. Write to support your AppSumo coupon and we will upgrade your existing account.