[TYPO3] Missing extensions in 4.0

[Jennie Z.]

I've just installed 4.0 and am trying to install some extensions 
(specifically,  tt_products)
When I connect to the extension repository  I only see about 75% of what 
was previously available on 3.8. I'm not getting an error message or 
anything like that... the list is just incomplete.

I went into settings and checked the box for unsupported extensions. Now 
the entire list is there, the missing extensions highlighted in red, 
which means I probably* *shouldn't use them in 4.0.

Has anyone used tt_products on 4.0, or any other older extension? I just 
want to know if it will have major problems, in that case I would go 
back to 3.8 for the time being.

Thanks in advance!

-Jennie