a suitable version for old hardware
 

i've got old hardware what's the suitable version to use ?

Check out Lubuntu / Puppy linux.

Old is a relative term... Without knowing the make and model or its specifications one can not say what will be suitable.

It probably is more important what you want to run on it. Just about any disto and version will be ok. Disk space is more important, and if you want to run any programs needing heavy CPU/memory.

Ive a basic file server on 90s era hardware running CentOS just fine. But its a barebones install with only the OS and a few file tools.

Thats one of the good things about *nix, its not really dependant on hardware, the way windows or apple OS's are. For a better example, just look at all the *nix based OS's running on all these microprocessors now.

In addition to the above, antiX works on most any old hardware. If investigated, also look into SMXI for post-install tweaking.

A minimum of 512MB RAM is recommended for any, but antiX and a few others run on less (including Puppy Slacko 5.5)

What are the specs of your hardware? That will help persons give you more knowledgeable answers.

Hi and Welcome to LQ!
As said from others, old is relative..
We need more info to help you: cpu, ram, etc..

Some reliable and easy Linuxes are

By minimum memory size:
512MB : Linux Lite, Mint (Mate version), Point, SalineOS
256MB : Salix (Xfce version), Vector Standard (Xfce version), ZevenOS
128MB : AntiX, Bodhi, Salix (LXDE or Fluxbox versions), Swift, Vector Standard (Fluxbox version), Zorin OS Light

By CPU:
non-pae CPUs (Pentium I, some early Pentium M): Bodhi
Pentium Pro is the minimum recommended by Vector, Pentium II by AntiX, Bodhi, Swift, and Zorin OS, Pentium III by the rest

If you can't use a DVD and have to boot from CD, then AntiX, Bodhi, Salix, Vector, or Zorin OS Light are available.