If you're going to provide Klarna services (KCO or KPM) to more than one country you have to make sure that you have created all of the corresponding currencies and languages in your store.
Let's take an example: I'm setting up Klarna in my store for Sweden and Finland, My default settings in the store at the moment are aimed for Swedish customers, however, I also need to create the Euro currency and Finnish language for my Finnish customers in store administration under: Localization -> Currencies and Localization -> Languages
If you're enabling more than one country in Klarna integration and miss some of the currencies/languages, you will encounter issues with the checkout or when a customer tries to submit an order.
This integration is developed with all the necessary standards of PrestaShop with the default template (default-bootstrap). Some merchants encounter problems with the integration together with third party templates. Here comes a list of things you should control:
The following callbacks are not implemented
If you use Klarna KPM services it is possible to get a status from Klarna for Pending Invoice or Pending Partpayment.
Orders with these statuses, should not be delivered until Klarna are complete with their evaluation.
It is possible to set up a cronjob for the following url, it will make a check and change status of these orders as the status is changed in Klarna.
If you don't set up a cronjob for this, you will need to check these orders in Klarna Online or by clicking the button on the order details page.
If you intend to use an EPM with the Klarna checkout, a prior approval is required from Klarna as part of the contract. Note that merchant account would also need to be updated post approval to display the EPM on the checkout. The feature in the module supports redirect to default checkout or an external checkout, but the later requires additional effort on part of merchant as mentioned here.
The country specific language text in the Klarna payment method widget can be displayed by configuring the supported locale value in the language code field for the languages available in Localization -> Languages. If the value is incorrectly configured, then the fallback language for widget text is English. For example, to configure Swedish, input language code "se-sv".
The supported locale can be found here.
Please note the requirement to use decimals for currencies. The minimum requirement is to set 2 digits for decimals to minimize the chances of incorrect order and tax total calculations. Reference.
Please note the requirement to use HTTPS for all of your interactions with Klarna API, which requires SSL certificate installed on your website Ref: Merchant URLs.
To give your customer a elevated shopping experience in the Klarna App, please include the shipping info (Shipping Company & Tracking number) for each (KCOv3)order in the Backoffice. When Klarna orders are activated/captured, the shipping formation is shared with Klarna, which would enable Klarna to show shipping status updates in the customer's Klarna App. This will also decrease the chance of customers reaching your support team regarding shipping updates. Ref: Delivery tracking.
You may be required by your Klarna contract to provide Extra Merchant Data (EMD) for your orders (more information here). If that is the case, you will need to configure this option within the Klarna Checkout module files. After installing the module on your store, create the folder /override/modules/klarnaofficial in your PS installation. Add a new klarnaofficial.php file there, which will contain the necessary data in the form of an attachment (more info here).