After upgrade to 4.4.1，The Filter can't work!!

Hi,

The issue is linked to the customization you have. The view overrides you have are based on old versions of HikaShop which don't support the new ajax system of filters we've added 2 years ago.
So you need to look in the folder templates/YOUR_TEMPLATE/html/com_hikashop/product/ via FTP.
There, you should find many files.
It's likely coming either from the files listing_div.php or listing.php or filter.php or a combination of these.
You'll have to rename them one by one, clear your website cache if any each time, and check if it helps until you find the ones causing the problem.
Then, you can either keep the files renamed if that doesn't mess your listing look, or copy / paste your modifications to the new version of the view files via the menu Display>Views to redo the overrides based on the lastest version.
Finally, note that with HikaShop 4.4.2, you can have a "diff" of the changes in the view overrides so it can be a great help when checking what is different between your view override and the default view file of the current version of HikaShop:
www.hikashop.com/home/blog/467-hikashop-4-4-2.html