Since iOS version 7.1.1, giffgaff became an official Apple carrier, which makes using an iPhone on giffgaff much easier. Therefore, if you are using iOS 7.1.1 or above your MMS & Internet settings will be installed automatically when you insert your new giffgaff SIM.
However, if you are using an older version of iOS we advise you to update to the latest version. If you are unable to update to iOS 7, please refer to this guide here to manually update your settings.
To update your iDevice to the last available version of iOS go to:
General - if there is a newer version available, a notification is displayed next to the label
The details of the version are displayed, tap "Install now"
Read and accept the Terms and Conditions
The installation starts
Your iDevice will reboot
All done, enjoy the new version
It's also possible to update iOS to the latest version by plugging your iDevice into your computer. Launch iTunes and select your device. You can then check for the latest update and install it.
During the update, if prompted you should reset the carrier profile - this is the default answer. This will make sure that you are using the most up-to-date Internet and MMS settings.
This will replace your current profile with giffgaff's Internet settings, including the parameters which can't be modified manually (e.g. proxy settings). MMS settings must be modified manually, see below.