cannot import library backup help!

Hi,

I'm trying to import from a library backup and get this error message

calibre, version 3.15.0
ERROR: Not valid: The folder /home/curt/Documents/library backup 1-23-2018 is not valid: The exported data in part-0015.calibre-data is not valid, version (837539839) is higher than maximum supported version. You might need to upgrade calibre first.

Traceback (most recent call last):
File "site-packages/calibre/gui2/dialogs/exim.py", line 257, in select_import_folder
File "site-packages/calibre/utils/exim.py", line 256, in __init__
ValueError: The exported data in part-0015.calibre-data is not valid, version (837539839) is higher than maximum supported version. You might need to upgrade calibre first.


I've tried downloading and installing the latest windows and linux versions and both return this error.

Is there a way to extract the individual archives and recover the books instead?

I'd really appreciate any help