Adding address_firstname to order status notification email

-- HikaShop version -- : 3.4.0

How can I add address_firstname and address_lastname to "Order status notification" email message?
I'm using guest checkout. First and Last name is saved in Display > Custom Fields > address table.
Tried adding Hello, {TXT:ADDRESS_FIRSTNAME}. to the email and that didn't work.

Hi,

You can use such tag: {VAR:billing_address.address_firstname}

Thank you! How do you get user registration email? I tried {VAR:email} but it didn't work.

It's {VAR:customer.user_email}

Thank you. {VAR:customer.user_email} doesn't display email address but you did point me in the right direction and {VAR:user.user_email} seems to work. I have guest checkout enabled, in case that matters.