[GNC] GC v4.1 on Windows and v3.1 on Ubuntu

[Larry Long]

 Is the same GnuCash database compatible back and forth between v4.1 and v3.1 applications?
I run GnuCash on my Windows PC at home. However, when traveling I like to copy my GC database onto my little Ubuntu notebook and enter new data while away from home.When I return home, I copy the updated database file back onto my Windows PC.
Adrian has me interested in updating my Window copy of GC to v4.1, but I gather that there might be issues in getting my Ubuntu edition of GC updated to v4.1.  
Thus, my question as to whether I could use GC v4.1 on Windows, copy my database to my notebook, update the data with GC v3.1 and then painlessly bring the database back for use with v4.1?

Unfortunately, I don't remember the format of my GC database and don't see how to display it.  As I recall, I just accepted the default during installation.
Thanks in advance for any advice.
Larry Long