Where are firmware updates for several Zyxel products? (VMG8825-T50K / VMG8924-B10A / LTE3301-Q222)

Hi,

It used to be easy to find firmware updates for my Zyxel products, however, nowadays I cannot find anything for these products from any Zyxel download site:
VMG8825-T50K
VMG8924-B10A
LTE3301-Q222

I've looked at these places:

https://www.zyxel.com/fi/fi/support/download_library.shtml
https://www.zyxel.com/support/download_library.shtml
https://www.zyxel.com/support/download_landing.shtml

However, no firmware available for these products, no version at all. For instance search at Download Library | ZyXEL cannot find any products starting with VMG, like products starting with VMG would not exist at all (!).

Please let me know how to find the latest firmware for the above products?

Thank you!