Virtuemart add to cart or refresh cart not working after upgrade Joomla 3.10.11

[duplexau]

Hi,

Our VM version is VirtueMart 3.0.18

We have performed manual upgrade of Joomla to 3.10.11 via FTP overwriting files (PHP version is 7.4) in the following order:
- Joomla_3.9.x_to_3.9.12-Stable-Patch_Package
- Joomla_3.10.0-Stable-Update_Package
- Joomla_3.10.x_to_3.10.11-Stable-Patch_Package

We also updated theme Shaper Helix to 3.0.3

For some reason, when I navigate the virtuemart shop category page and try to click "add to cart" or refresh mini cart, virtuemart seem not responding anymore.
Any resolution or workaround is greatly appreciated, thank you.

[GJC Web Design]

You don't mention VM versions .. and check for JS errors in the console

[duplexau]

Okay, sorry about that.
The VM version is 3.0.18


Here are the JS errors for reference:
Refused to apply style from 'media/plg_system_browserupdatewarning/css/BrowserUpdateWarning.css' because its MIME type ('text/html') is not a supported stylesheet MIME type, and strict MIME checking is enabled.

BrowserUpdateWarning.js:1     Failed to load resource: the server responded with a status of 404 (Not Found)
jquery-migrate.min.js?f364abd7665064b92a2f29fb394cf9fe:2 JQMIGRATE: Migrate is installed, version 1.4.1

Refused to execute script from 'media/plg_system_browserupdatewarning/js/BrowserUpdateWarning.js' because its MIME type ('text/html') is not executable, and strict MIME type checking is enabled.

[GJC Web Design]

The VM version is 3.0.18

Really?  the latest is 4.0.20 so I really doubt you will get much help here for such an out of date install... it's from 2016!!!