[Users] syncing Claws from Windows to Linux?

[Norwid Behrnd]

+ For email sent and received this is be possible if e.g., your mail
  server supports the IMAP protocol (emails remain on a server, CM
  only fetches a copy).  Your question doesn't state if it is
  accessible to you, or not.

+ Using a LDAP server about the addresses within one's own
  school/business network isn't a synchronization of address books,
  yet provides access at least to this subset of data.  (To sync the
  .ldif files about the address books might be possible if using a
  thumb drive to shuttle them is permitted.)