Do you know how to convert V4 file to V5 file? You can do it Catia V5 for V4 to V5 file migration.
Open the version, V5 Catia.
Load the V4 file.
Click the icon named send to V4 to V5 migration
Table of V4 to V5 migration pop out, select the master on the spec tree, edit the location of the output directory (example: Desktop), and click Run.
Click close when the migration status achieve 100%. Then go the location for output directory and load the V5 file.