Outlook Crash

Dear Friends,

I am facing lots of challenges when I open outlook (old version) it crashes and only option I have is to force quit the same. I had problem earlier and when I changed to new version of outlook it got resolved. After iOS update I tried if above issues are fixed, so I moved to old version of outlook and since than I cannot open outlook. Already tried downloading app and updating as well but still it is opening old version and it doest allow me to change it to new version and I cannot use the app. Please help!