As long as you follow the 'Upgrading to a Pro Viewer' instructions here, all should be well: http://www.simpleviewer.net/svmanager/support/#svpro
Please make sure of the following:
(1) Use the Pro 'jbcore' folder from the Juicebox-Pro download zip package ('juicebox_pro_1.3.3/web/jbcore/').
(2) Copy the complete Pro 'jbcore' folder into the 'svmanager/plugins/juicebox/jbmaster/' folder. (Make sure that you do not copy the complete Pro 'jbcore' folder into the 'svmanager/plugins/juicebox/jbmaster/jbcore/' folder, ending up with a path like 'svmanager/plugins/juicebox/jbmaster/jbcore/jbcore/'.)
(3) If you are in any doubt as to whether or not the existing 'jbcore' folder on your web server is being overwritten, try deleting it from your web server first before uploading the Pro 'jbcore' folder in its place.
All subsequent galleries created by svManager will be Juicebox-Pro galleries (using the Pro 'jbcore' folder).
Please note that any existing galleries created prior to upgrading svManager will need to be upgraded individually.
SimpleViewer Support Team