1. Add "$emailcharset = "UTF-8";" in config.php

That's a correct line added to config.php.
I forgot "-8" while reporting bug. In my config.php this line is correct ($emailcharset = "UTF-8";)

"extra quotas" = "extra quotes"

Please upgrade to v1.87RC4 and tell us, if you still can reproduce the issue - THX!
Background information: we upgraded to the lastest version of PHPMailer libary and many issues are fixed in that version!

@ sp00ky: any news? Please provide feedback!

ok, i've got 1.87RC3 (last possible to download)
and...
...it's not working :(

its 1.87RC4 (8004)
but it's still called 1.87RC3 in download section

@ c_schmitz: do you have an idea?

Well,

according to http://www.ietf.org/rfc/rfc2045.txt both forms are allowed
Question is if that is really the problem.

Sp00ky, is that really the only difference?

Also try
$emailcharset = "utf-8";
in config.php (not the lowercase)

I guess it is a bug in Lotus notes not handling the charset correctly.

I think I solved it - this bug is related to
http://sourceforge.net/tracker/index.php?func=detail&aid=2864280&group_id=26031&atid=385707

Fixed in rev 8081

@c_schmitz I've tried "UTF-8", 'UTF-8', "utf-8", "Utf-8", UTF-8 and every possible combination :)

that's not because of quotes, but spaces before and after "=" (related link)

line
$result .= sprintf("Content-Type: %s; charset = \"%s\"", $contentType, $charSet);
should be replaced by
$result .= sprintf("Content-Type: %s; charset=\"%s\"", $contentType,
$charSet);

I've changed it in class.phpmailer.php and everyting is allright :)
Now it looks like this:
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

Thanks a lot!

PS. this bug was reported on PHPMailer bugtracker in 2003 :))