Multipe JARs of same library

Hey there,

i am using the DEB repository for my Debian 9.
After upgrading from 2.0 to 2.1 i saw many double JARs in /var/lib/openhab2/kar

is it safe to delete the 2.0.0 jars? are they still needed??!
How does it work? where does these jars come from? after a fresh install there is no kar-directory in var/lib/