Is there an easy way to add the default language code to links (url)?
CS-Cart 4.17.2.SP3
Please clarify your problem in more details
It can be set in the configuration to add the language code to the links. However, this cannot be set for the default language in the shop (in which case the language code is omitted). I made some changes in the seo add-on, thanks to which the language code was pasted to the ulrs of products, categories, pages, etc., but the functionality of logging in or adding a product to the cart stopped working (after an ajax request the info that the page does not exist appears)
You can ask CS-Cart support to provide you with the archive of old CS-Cart version and compare the SEO addon files. The SEO module displayed default language on the old versions