wp_mail attachments support only ascii symbols

[Fike]

Hi.
Currently wp_mail() passes it's attachments directly to PHPMailer, and that results in taking file basename as attachment name. Basename seems to behave not normal on non-ascii symbols, for example /сontacts.png (the first 'c' is russian) will be truncated as ontacts.png. Apart from that, even if it would be basename'd correctly, it won't be utf8-encoded as required by standard (=?utf-8?B?base64?=), and that will probably result in broken mails and/or rejected mails.

So i'm proposing to implement functionality for manual attachment naming and/or automatic basenaming filenames and encoding attachment names according to ​standard.

#28407 is tightly bound to this request.

[cbutlerjr]

Would resolving #28407 resolve this?

[ocean90]

#49033 was marked as a duplicate.