Acrobat Reader won't open with iOS 10 on an iPad

iOS 10 was installed on my iPad yesterday, and I cannot now open Adobe Acrobat Reader. Sometimes the front 'Acrobat Reader' page appears, then freezes and crashes. More rarely, after a delay the list of files will either appear but then immediately disappear or will appear for a monent, then crash and disappear when I try to open one. I would appreciate help urgently as I keep a lot of material in Acrobat Reader and at present the system is completely unworkable.