updating whatsapp on older IOS
whatsapp is not allowing me to access the app, requiring me to update whatsapp before doing this - unfortunately this is not possible since it requires my phone to have a certain IOS in order to update. However we cannot update the IOS as it requires a certain amount of data to download - data which is not available since the phone does not have enough storage. It is impossible to free up storage (I have tried this but overall it is negligible since the phone has very little storage anyway). I have tried putting the SIM card in a newer model but I can't transfer whattsapp data (because whattsapp does not allow me to access settings - only shows the update screen).
Please give advice, thank you.
iPhone 5s