I use Android's stock email client "com.android.email" version 8.1.0 on Samsung Galaxy J5 running LineageOS.

I noticed that the emails are sent using

Content-Transfer-Encoding: base64

I'd like to change this to something like

Content-Transfer-Encoding: 7bit

Going through the email client's options, I couldn't find anything relevant. Is there still a way to change the transfer encoding for the email body?


1 Answer 1


The AOSP Email client has only support for base64 (text body and attachments). This is hard coded in the source code hence you won't find any UI setting to change it. The source code even contains a comment on this topic:

Note this always uses base64, even when not required. Slightly less efficient for US-ASCII text, but handles all formats even when non-ascii chars are involved. A small optimization might be to prescan the string for safety and send raw if possible.

Rfc822Output.java line 354 to line 385 (relevant function for text encoding in the source code)

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