From version 2.0, Kartris has supported HTML emails. This functionality can be turned on with the general.email.enablehtml config setting.
Naming templates correctly is important to ensuring that the system can locate and use the appropriate template. The templates are located within the skin, in a folder called templates. The following template files should be present if your site is running in English:
For other languages, you should have similar templates with the appropriate language culture code in the name, for example Email_OrderConfirmation_DE.html for German, Email_OrderConfirmation_PT.html for Portuguese, and so on.
If you have upgraded a skin from an older Kartris, you may be missing some or all of these templates in your skin. From v2.5009 onwards, Kartris writes clearer error messages if templates are missing.