Clients must include the attribute options when using an attribute name following a mod-spec. Consider the following LDIF:
# wrong dn: cn=test,c=us changetype: modify replace: your-attribute-name your-attribute-name;binary: binary-stuff
your-attribute-name must contain the option (binary in this case). Here is the corrected LDIF:
# right dn: cn=test,c=us changetype: modify replace: your-attribute-name;binary your-attribute-name;binary: binary-stuff
ldapmodify tools (notably the legacy OpenLDAP ldapmodify tool) and directory servers accept the first wrong LDIF as correct. Be sure to follow the standards.