Hi,
The specifications tab only displays when you have custom fields of the table "product". And when you fill the custom product fields in the product, the filled data will appear in that tab.
There was never a version of HikaShop where you could make your own tabs. I suppose you're talking about using the Tabs & Accordions plugin from Regular labs (
regularlabs.com/tabsaccordions
). With it, you can directly add tags in the product description to have tabs inside the description. And so, you can use the default layout instead of the tabular layout and use your own tabs instead of the ones generated by HikaShop.