I am pleased to let you know that ZeroDrive 1.6.4 is now released. This release will address an issue related to the Hotspots on downloaded files, a feature introduced in  ZeroDrive 1.6.0 release. 

 BUG FIXES Border appearing for Hotspots on downloaded files when visualising the file with certain PDF viewers has been removed. As this was not experienced on all PDF viewers, you may have not been able to reproduce it. 

Before fix: 

After fix: