Company: lets develop a cutting edge, SaaS software solution that would make our current software obsolete.

Also Company: needs to be fully compatible with IE 11. Oh and also use it as a base for testing performance and UI rendering.

Fffffffffffffff.

What's the problem with ie11?

No it hasn't.....

IE 11? I'm pretty sure what they meant is, the new SaaS is not meant to be completed, as I doubt you guys will be able to finish it if IE is your standard ...

@CorruptComputer @Jop- so...?
Android 4.4 is old too but still supported, you cannot always only support the newest version, you have to cutoff at some point where you support the majority on platform users with in reasonable investment of deployment.

@CorruptComputer following your logic you should support only 7.1.2 and O DP4
Why bother supporting 5.* or 6.*?

I know it's not popular to say "chill mate and support the client" especially when it has anything to do with MS tech.

@CorruptComputer well you are building the site for the users to use not the browser. As long as your target audience uses IE11, not supporting it will be losing revenue.

@Jop-
a. Some users don't know they can update/change.
b. Some users don't feel the need to update/change.
c. Some users might be restricted and cannot update/change.
d. Some users don't know how to update/change.

As long as these users are bringing revenue to your site/application you should support their platform as long as the investment doesn't out weight the benefit.