Hi,
It could be because you have view overrides from old versions of HikaShop.
So go in the menu System>Emails. And if you have customizations for the emails, try to remove them (save the changes in them before) and then add back the changes to the new version of the email code and it should work properly.
For the order, supposing that we're talking about the order details page on the frontend, check that you don't have the file templates/YOUR_TEMPLATE/html/com_hikashop/order/show.php
If you do, rename it and it should display.