Hi,
You can still edit the emails in the menu System>Emails.
Please note however that the email edition interface is only available with HikaShop Business.
It seems that you were using the Business edition before, but you are now with an Essential edition, so the problem is not the fact that you updated your version, but that you downgraded your edition of HikaShop.
If you want to upgrade your HikaShop back to the Business edition, you can go in the menu My account>My subscriptions on our website and click on the upgrade link for your subscription. Once the purchase is done, you'll have a download link there to get the Business edition install package and you'll be able to install it on top of your Essential edition to get back all the features of the Business edition.