Re: How to migrate Nexternal eCommerce users to magento 1.9?
I think you should choose Magento 2.x over 1.9 since Magento 1 has reached its end of life date in June 2020, which means there will be no regular software security patches and features update. To migrate your store, you can search for some top automated migration experts/service providers. Your current platform can yet be in their list, still you can contact them for a custom project. Visit my timeline or direct contact me for specific recommendations.