For most integrations, we can send new variant information to your Point of Sale or eCommerce from the opposing platform.
With the exception of BigCommerce, all of the other integrations we work with can sync new variants. BigCommerce, unfortunately, does not have the ability to accept new variants for existing products.
Every other platform however, can accept new variants from existing products! So, if you were to have a set of t-shirts and needed to add a new color or a new size, those new variants will push to the opposing platform from the one you've added them to.
If you run in to an issue where adding new variants to an item do not sync properly to the opposing platform, it is recommended that the original item and variants are archived on both platforms and then recreated on one side and then pushed to the other. If you have questions in regards to this, please contact Support.