I have a special character in my surname (Böck), so it gets encoded in the "From" line.
Claws mail uses an utf8/base64 encoding, thus it becomes =?UTF-8?B?QsO2Y2s=?=.
Base64 encoded mail headers are often used for obfuscation by spammers, and spamassassin has a filter rule (FROM_EXCESS_BASE64) which can give - depending on the configuration - up to 1 point in spam rating.
I'd rather like to avoid that, but I think right now claws has no way to configure the header encoding. (As a workaround I can however set an already encoded name in the account config.)
Would it be possible to change claws to use quoted printable encoding instead of base64?
Go to the /Configuration/Preferences/Send page and set 'Transfer encoding' to 'quoted-printable'
ignore comment #1, i was mistaken