After upgrading XWiki from 5 to 7.1 version,
international characters in
 watchlist email notification message are corrupted (different charset).
 I tried send XWiki page using "Share by Email" and international characters
 are OK.
 Is there any way how to solve this problem?
 I tried switch XWiki.WatchListMessage language to SK, but nothing was
 changed.
  
This sounds like the following bug:
  
http://jira.xwiki.org/browse/XWIKI-12244
Can you update to 7.1.2 where it should be fixed and try again?
HTH
Clemens