An important question [Spoilers]

It is unclear whether she was raped, however there was strong evidence of violence.

No rape. He was too clumsy. She starts screaming, a struggle ensues, he knocks her out, but has also cut his foot during the struggle. One thing left to do: Flee (and forget wallet and keys)

I think it’s unknown to us if there was a rape, I think it’s meant to be. There is no clear indication either way.

We know one thing for sure, when Emad asked him why he went into the bathroom even after he realized that it wasn't the woman that lived there before, he responds by saying "I gave into temptation." I interpret this as an attempted rape at least if not more.

I don't think it was rape for several reasons.
The old man was not capable of it.
It would introduce all kinds of complications in that fundamentalist country.
Just the hint of it was enough to drive the story.

This was a surprisingly good movie, very good, but on Amazon Prime the extreme ends of the subtitles were often truncated and it was hard to figure out what was being said.

No, there wasn't time. Rana screamed, the glass broke, and the neighbors heard the noise. By the time they got to the stairwell, the old guy had already run down. He wasn't a rapist anyway; just a feeble old man who wandered into the wrong apartment by mistake and fled as soon as he realized it. That's why Emad let him go with just a slap.