I see two ways to solve your problem:
Set the email header with the desired Content-Type, in your case: Content-Type: text/html; charset=UTF-8
This can be done through your customer sending emails in bulk. For example, in Django this is done by setting this way:
msg.content_subtype = "html" # Main content is now text/html
The charset will be set according to the charset of your Django instance.
The other way is to use the codes or HTML names of the special symbols you send.
For example:
<p>Administração</p>
Becomes converted to:
<p>Administração</p>
Or to
<p>Administração</p>
For this you can use the following converters:
http://www.web2generators.com/html/entities
http://www.emailonacid.com/character_converter/
References
http://www.emailonacid.com/blog/details/C13/the_importance_of_content-type_character_encoding_in_html_emails
http://www.ascii.cl/htmlcodes.htm
http://en.wikipedia.org/wiki/List_of_XML_and_HTML_character_entity_references
From what I read in the article, these tags should be avoided, but it does not mean that you can not use, remembering that this article is from 2010, some things may have changed from there to here. When I send Mkt emails or other types I always make the html complete. I go to see if I’m doing wrong but never gave me problems.
– Marcelo Diniz
Opa Marcelo, I also always send with all HTML, but I noticed for a while that most of the developed e-mail are falling into spam or trash, I believe that for these usability, I will make these changes and see if the data change or remain.
– CRAJ
I don’t know if these usability are fault to fall in span, some may be that yes, as a goal, I don’t know, I’m just talking, but it may be falling in span for other questions of setting up the mail server, I would look at this before to resolve this issue of span.
– Marcelo Diniz