updating old technology - help!?

Hi All, I'm wondering if anyone has suggestions on how to update an old ipad with pdf reading/editing software? Due to more home-office/lack of printer I've turned back to an old ipad which is completely functional and in great condition but will not update itself to the latest operating system. Which means I cannot use/update any pdf reading software. Anyone have any suggested work-arounds? IT response was that Apple stops updating when the operating system is too old. But I find the solution to get a new piece of tech to replace a functional old one very unsustainable. In general it would be great to think about how we can refurbish, re-use and share tech at SRC. Thanks for any tips! Jamila