To install an IPA file, you cannot simply "open" it on your phone. You need a sideloading tool:
If you are using a legitimate IPA backup of your own, you can install it using these common methods: total war medieval 2 ipa install
While less stable, tools like Esign or Applejr allow for direct IPA signing and installation via Safari. To install an IPA file, you cannot simply
: Features a completely redesigned user interface specifically for mobile touch controls. Grand Campaign To install an IPA file
Using a signing service like MapleSigner to upload the IPA and a mobile provision file.