Hi, thanks for choosing Dell. The OS 8 is too outdated, I'm afraid. (OS 9 is okay) Please see the link below. https://dell.to/3N1Lnsb

So are you saying it is not possible for me to upgrade to OS9?

Hi, Unfortunately, I can't find older versions as well. I don't have reach to force10 websites if you have you can check there for archive OS8 versions. I'm not sure Dell Digital Locker has Force10 OS8 versions but also you can look there. 
I couldn't find for S4810 but there are some S series Force10 OS8 Software https://dell.to/3wVqKXW

How to Install Dell Networking FTOS on Dell Open Networking (ON) Switches https://dell.to/3t8GPIH

From what I've been able to tell, any force10 website link redirects to the same Dell page.

Hello Diver_1845,

I picked up your post. Young is currently out of office.

I'm still in progress trying to find 8.3.12.0.  I'll also update Young.

We will follow up when we have more information.

Charles R,

Thanks for your help.

Hi Charles got you this. Hope this helps. https://dell.to/3NdUiHl

Login credentials:  

User = NAmmEGE9E9
User Password = 6IwJJ622JG

Hello DELL-Young E and Dell -Charles R

I am facing the same problem! I was also unable to find the OS8 firmware (8.3.10.2). I accessed the link provided, but the username and password are not valid anymore. Please, can you give me another credential to access the system to download the firmware?

@Dell-y

Thank you.

Hello shyfimacks,

I will have to look into this an update you.