Content-Type: text/plain; charset=utf-8

General
1

An EmailMessage with PlainBodyText defaults to Content-Type: text/plain which is rejected by Verizon when sent to any mobile_phone_number@vtext.com or mobile_phone_number@vzwpix.com but if that is changed to Content-Type: text/plain; charset=utf-8 using EmailMessage.Headers.AppendHeader then it gets accepted. This is a new requirement by Verizon.

Do any email gurus know why Verizon might have changed the requirement? Should Content-Type: text/plain; charset=utf-8 be the new default for an EmailMessage with PlainBodyText since it works with every other domain that I’ve tried? If not, is there an easy way to determine when Content-Type: text/plain; charset=utf-8 should be used instead of Content-Type: text/plain?

2

Bump . . .

3

Have you tried other values for charset? My guess would be that someone decided to require explicitly defining the encoding, rather than making the receiver guess.

4

I hadn’t but just did and Content-Type: text/plain; charset=us-ascii was also accepted. Since Content-transfer-encoding: 7bit is the default, I should be using us-ascii. Thanks Paul.