The Last of Us Remastered. It is - finally - time. [No Spoilers].

[Ser_Kafka]

I've just reached the University. I didn't find any tools in the area before, so I did check online and yep - I missed tool 4. Now, tool 5 is in the university, can I still upgrade my weapons? Will tool 5 supercede the tool 4 requirements?

Absolutely absorbed with this game.

 

[Palette Swap]

I've just reached the University. I didn't find any tools in the area before, so I did check online and yep - I missed tool 4. Now, tool 5 is in the university, can I still upgrade my weapons? Will tool 5 supercede the tool 4 requirements?

Absolutely absorbed with this game.

Click to shrink...

I've always taken it as "4 tools" rather than "tool 4" if that makes any sense, so I'd say you'll be locked out of any upgrade that requires level 5 tools. You can't upgrade everything in one playthrough anyway, and tool levels carry over to NG+, so you'll find the one missing tool in NG+.