[Affinity iPad - How to save selection for use in another project]

I'm having trouble exporting my .afphoto file from my iPad Pro Affinity Photo to my Mac version of Affinity Photo. 

I tap on Save a Copy on the iPad version and it exports to iCloud perfectly. But when I try to open it on my Mac I get this:

 

"Failed to open document

The file includes features from a later version of Affinity."

 

iPad is running version 1.6.3.43

Mac is running version 1.5.2

 

Any help is much appreciated!

Thanks