Physio true up - transfer

Hi,

Tell me please if I have Fenix 5 and some older device e.g Fenix 3 or Forerunner 10/405/610 etc is it still possible to transfer training data to Fenix 5 from those 'old' devices?
I understand that I cannot transfer data the other way round - I mean form Fenix 5 to Fenix 3, can I?

I am especially interested in training load data (I would like to use this older device for my martial arts training)

Regards