Re : Whatches and Mail sender
in 1.8, the mails are sent via the php function mail but the header encoding is not done. So if you message subject contains accent, special character, there will be sent in utf8 but there will be no indication in the header that it is utf8
in 1.9, the mails (a lot of them, some are still missing) are sent via the library htmlMimeMail.php that uses the php function mail. But this library encodes properly the header. + in 1.9 you can give the default encoding the mail are sent in admin general (utf8/iso8859-1) and/or each user can give this info in his preferences
some more info in TikiMailNotes
sylvie