Q: Why iranian people can't download or update the app???

Aw4n wrote:

 

So here's my problem. I visited Iran back in July and was able to access the app store and download Ark VPN for my iPhone without any problems except for slow internet.

 

Which App Store (I.e. What country settings is your store pointing to) were you using? It most certainly was not the Iran App Store because there is not and never has been any such thing. You were accessing another country's App Store, so, which one was it?

Most if the time you will find your native country's App Store unavailable or at least some content unavailable when accessing from a foreign IP or network. There are occasionally times when it may work that you can access your native store while abroad but there is no guarantee it will be possible or reliably so.

Regardless, since there is no Apple App Store native to Iran, the question is moot. Apple does not support products or services in Iran.  So if an Apple product or service does not work there, Apple has nothing to explain, since they do not do business nor provide support in that country.

There was NOT "support" there 2 months ago. You got lucky, that's all. Many service providers, not just Apple, are cracking down harder to filter out traffic from Iran in an attempt to control illegal purchases of content that is not licensed for sale in Iran.