Have Sage 50 2018, but my bookeeper seems to have a 2019 version and I can't open my files

SUGGESTED

I bought the 2018 version and I can't open my files.  My bookeeper has the sage 50 cloud version which seems to be the earliest version.  I can only access my files from his version.  I've tried downloading the trial version 2015 and its still not working. 

What can I do?