It seems that this has been fixed in Xenial or at least I don't see this in logwatch at Thu, 21 Jan 2016 15:04:42 +0200 (EET).
** Changed in: logwatch (Ubuntu) Status: New => Fix Released -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1532252 Title: Unescaped left brace in regex is deprecated To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/logwatch/+bug/1532252/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs