Itunes library.itl "created with a different version" error

[Tairetsu]

So my sister asked me to fix her Iphone 4s,she has that common problem of the phone´s wifi fucking up when you updated it to Ios7,since I cant seem to find any solutions online I figure the easiest way would be to just downgrade the OS back to some version of Ios6,methods for which Apple seems to be highly against,as it looks like they render them invalid with every update to their software,so whatever,found one that´s recently so here hoping it works,thing is I need the version 11.0.0 of Itunes,now I only installed Itunes once,to try to mess around with it,but now that I install it again,from an installer of the 11.0 version the Itunes.exe gives me the error "Itunes library.itl created with a more recent version of Itunes".

 

So I imagined that it would have some kind of register that I ever installed a more recent version of it (keep in mind I downloaded Itunes from 2 different sources and try them in 3 different computers) but it sure as hell is not a file kept in the install folder,as the Itunes folder in Program Files  gets deleted when you uninstall it,and I have no idea where the register may be stored,or if that is even the issue here,so...any tips?

[Aniallation]

So my sister asked me to fix her Iphone 4s,she has that common problem of the phone´s wifi fucking up when you updated it to Ios7,since I cant seem to find any solutions online I figure the easiest way would be to just downgrade the OS back to some version of Ios6,methods for which Apple seems to be highly against,as it looks like they render them invalid with every update to their software,so whatever,found one that´s recently so here hoping it works,thing is I need the version 11.0.0 of Itunes,now I only installed Itunes once,to try to mess around with it,but now that I install it again,from an installer of the 11.0 version the Itunes.exe gives me the error "Itunes library.itl created with a more recent version of Itunes".

 

So I imagined that it would have some kind of register that I ever installed a more recent version of it (keep in mind I downloaded Itunes from 2 different sources and try them in 3 different computers) but it sure as hell is not a file kept in the install folder,as the Itunes folder in Program Files  gets deleted when you uninstall it,and I have no idea where the register may be stored,or if that is even the issue here,so...any tips?

 

Go to the computer's music folder, go into the iTunes folder, and deete the iTunes Library.itl file