Change color of specific vault with old version

With the older versions I think you used the Theme Editor (it's been a while since I had to do this): M-Files Theme Editor | M-Files Catalog

Thanks Craig !

can you guide me what should I do with this link to change color's vault? I have never come across this link

As I said: it's been a while since I did this so I don't have specific guidance.  As a partner you could post in the partner group, or reach out to the local partner team for support.  That said: this is a five-year-old build so I don't know whether that will come into it.

There's a configuration guide under the Documentation section on the Catalog, please see that for supported theming options and instructions.