Why can't I update the file commander to premium?

[prodigy]

Hello everybody. I want to update my file commander to the version (3.1.13174) PREMIUM , but everytime I try to install it a message appears and the app didn't installed. Can anybody tell me what is this message and why does it appear? I've got this version from a friend of mine who told me the file commander premium is better than the ordinary one. I've tried to install other versions of the file commander premium ,but they are all the same. This message appears while installing some other apps, but I unistall the first version of the app then install the newer one and it works. But in the case of file commander ,it's a built in apps which can't be uninstalled. Is there a solution for this or not? This is a screenshot of the fault.

[Uliwooly · Accepted solution]

@Prodigy1

Simple, get it from the playstore instead of sideloading a paid app, this is NOT a warez forum.

[Qatrium]

You'll not be able to do this unless you root your phone and remove pre-installed File Commander first. And as uliwooly said, it's not a good idea to pick paid apps APK's and sideload them.