Hello
got this type of router :
hardware ver 4
even if the wiki says 32/4, while it's a 8/4, it already runs on owrt 18.06, i see also that one :
but wiki says 
Version 4.x of this device is fully supported since r49158 ( trunk )
can it run more recent version?
thank you
pps : pls, dont ask me to change hw 
32/4 means 32MB RAM, 4MB flash memory. So what do you mean with it's a 8/4?
4MB flash is just too small for everything more recent.
You could give it a try, but i wouldn't stack my expectations too high.
To be honest: This device is far beyond it's lifecycle.
The best is really to replace it with something stronger.
If the shipping wouldn't be so expensive (that's just an assumption) i would give you my old TL-WDR4300 with 8/64 for free.
we're not going to ask you, we're going to tell you ...
It cannot run version beyond a heavily downsized v21 image. So you are stuck with one of the stable releases of that branch. Recommendation has to be to get a new device unfortunately.