You cannot export from ACF4 and into ACF5. The way that these two versions of the plugin store field group and field setting in the database is completely different.
ACF4 had a single CPT named “acf” and this stored all of the field group and field information for the fields in the group.
ACF5 now has 2 CPT, “acf-field-group” that stores field group information and “acf-field” that stores field information. Fields are child posts of group posts and other field posts.
The only way to automatically transfer from ACF4 to ACF5 is to import to a site using ACF4 and then upgrade to ACF5.
