Old Version of Adobe Acrobat Not Working… Need workaround to retrieve files

Hello,

I have a iPad mini 4 and had been using the Adobe Acrobat PDF reader app to review files but the app no longer works now that my software system updated to 14.71; thus, I am wondering if the app would be updated to be compatible with the new system so I can retrieve my files? All my PDF files from school (since 2015) are shared here and if I can't retrieve them I would be losing a huge chuck of my research study/book documents. Please send help!!!!!!

CBJ