To me it looks like I've broken the prior behaviour while trying to fix LOG4NET-354 and LOG4NET-405 remedies that. *ouch*
Quoting: http://msdn.microsoft.com/en-us/library/system.net.mail.mailmessage.headerse ncoding(v=vs.110).aspx > The value of the HeadersEncoding property defaults to Encoding.UTF8 whereas Encoding.Default will most likely yield something different. Quoting: http://msdn.microsoft.com/en-us/library/system.net.mail.mailmessage.bodyenco ding(v=vs.110).aspx > The default character set is "us-ascii". Here they do not mention the default encoding, but it will most likely be Encoding.ASCII whereas Encoding.Default will most likely yield something different.