Getting Started

Can't sync *all* inbox email to iPhone

Hi all. For a long time there was a setting on my iPhone to sync an unlimited number of days' worth of email, but now I find there is some sort of cutoff. I can search on my Mac and find years worth of inbox email. But on my iPhone it only goes back a limited amount of time. Is there any way to get my iPhone and iPad to sync all email? I need this so that I can search for older email on the road without my computer. Thanks!