I've recently opened up one of my physics codes that was written in the 6.3 update times, and now with the 6.4 and 6.5 updates it doesn't even work anymore but doesn't give any errors either when running.

Why is this?

Well, if you dont show us some code or at least describe it i cant see a way to help you.

Anyway, i can tell that when i upgraded from 6.3 to 6.4 i noticed some problems with the physics engine behavior but that was because there was changes on the physics engine itself i believe, like the fact the physics entities movement were no more frame dependent, etc.

I noticed i needed to change the PE entities properties like friction, damping, elasticity, because they slide too much, its a matter of testing.

Well this is what I was primarily aiming for, it wasn't anything code specific really. I was just curious to what had been changed in the physics engine that would cause such a behaviour to occur and so on.

So primarily what factors would need changed to make the physics work? I know you said changing the properties could work, anybody know anything else that might be helpful?

Ok, maybe someone else has other factors in mind that could help on that matter.

Concerning to my experience, i had the code for the physics ball described in the manual 6.31 that worked very well in that version.

After update to 6.40 the code continued working but the ball no more had the precedent behavior, instead it rolls and slides much much more, then i had to change those properties, so the ball code never stoped working.

I must say its really strange that fact you are mentioning, i mean the code stop work, unless you changed in some way the code, like the registering procedure of the objects, or some kind of event (like even_friction) that eventually could stuck the objects somewhere..

Well, without further information its difficult, i hope someone can have other ideas. Sorry for not helping you much more.