Zoho incorrectly interprets incoming email Content-transfer-encoding when charset is not UTF-8

In nordic countries (Norway, Sweden, Denmark, etc.), Microsoft Outlook default setting is to produce email headers like this:

Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable

Content-Type: text/html; charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable

Zoho incoming mail handling to Creator Forms is misinterpreting this and replacing all international characters with just a <?> symbol. The text is then destroyed and cannot be processed because a lot of the characters become this ugly symbol.

The problem that Zoho has not understood is that even though the charset is iso-8859-1, the "quoted-printable" statement says that there will also be international characters in this text that are in UTF-8 encoding after an '=' byte.

An email body for the following text:

"The Norwegian alphabet has 3 important extra characters which are Æ, Ø and Å."

is therefore encoded in quoted printable this way:

"The Norwegian alphabet has 3 important extra characters which are =C6, =D8 and =C5."

and you destroy it consistently to become:

"The Norwegian alphabet has 3 important extra characters which are �, � and �."

The '=' is an escape character and the 2 next bytes always represent the UTF-8 encoded international character, even if the charset says something else. It is obvious that Zoho is not respecting this rule.

I have tested a lot and modified the email header manually as follows:

Content-Type: text/html; charset="utf-8"
Content-Transfer-Encoding: quoted-printable

and then it works perfectly!!

This only goes to prove that you are not handling quoted-printable header information correctly when charset is anything other than utf-8.

Our problem is that we cannot ask every person in all Nordic countries to change the default Microsoft Outlook email settings and all other email recipients handle quoted-printable just perfectly.

Can you please correct this bug now that I have explained it to you? This is a major blocker for using Zoho email interface for anything usable (especially because you destroy the international characters before we can try to fix them ourselves.

Best regards,

Eirik Y. Øra, +47 919 06 353 (Oslo, Norway)

- Hoping to see a fix shortly! (July 2023)