Firmware image required for MES3500-24F and MGS3520-28F

Hello Zyxel Team,

I am currently working on a firmware upgrade activity for the following Zyxel switches:

1. MES3500-24F
   • Current firmware: V2.00
   • Firmware date: 03/28/2012
   • Target firmware identified: V4.00(AABG.6)
   • Target firmware date: 08/08/2018
2. MGS3520-28F
   • I am looking for the latest supported firmware image for this exact model.

Could you please provide the official firmware image/download link for these models?

I would also like to confirm:

• Is the firmware image still available?
• What is the latest supported firmware version?
• Is an intermediate firmware upgrade required before upgrading to the target version?
• Is there any specific upgrade procedure or limitation for these EOL models?
• Could you provide the exact firmware image file (.bin) for the respective hardware model?

I want to make sure that I use the correct firmware image for each exact hardware model and avoid using an image intended for another MES/MGS series model.

Thank you.