UML 1.4 uses objects as lifeline symbols in sequence diagrams at instance level (sequence diagrams at classifier level are not supported by ARIS UML Designer 7.x). In UML 2 lifeline is a new element type, so that lifeline symbols are no longer occurrences of objects which could also appear in class diagrams.
If a UML 1.4 object occurs in a sequence diagram and in a class diagram it is migrated into a UML 2 lifeline and a UML 2 instance specification.
If the UML 1.4 object has a type the property represented by the corresponding UML 2 lifeline has the corresponding UML 2 type.