Where can I download the latest firmware and relevant documentation for end-of-life switch?

Zyxel_Kay

For switches that have reached end-of-life(EOL) status within the last three years, ZYXEL lists the model along with its firmware and relevant documentation on the following site:

https://webservice.zyxel.com/end-of-life

You can find the device firmware by filtering the category:

For models that have reached end-of-life status for more than three years, they may not be listed on the site. In such cases, please contact Zyxel Support by raising a question on the Community for further assistance.

For optimal performance and support, we suggest exploring currently offered switch models on Switch | Zyxel Networks.