Problem from the two last iOS upgrade

Since the last two iOS versions of Apple, I am no longer able to work normally with your app. The application freezes and no longer to focus the document when zoomed. It is now impossible to correctly annotate a document and save it. However I have worked for several months with your app without problem for personal purposes. I even wanted to extend the use of this app by purchasing a full version for several cellphones and iPads in the company. Please help me.