Historically, because of the wide range of systems and protocols that could be used to transfer messages, e-mail was often assumed to be non-8-bit-clean – however, modern SMTP servers are in most cases 8-bit clean and support 8BITMIME extension.
MIME defines mechanisms for sending other kinds of information in e-mail, including text in languages other than English, using character encodings other than ASCII.
QP encoding is reversible, meaning the original bytes and hence the non-ASCII characters they represent can be identically recovered.
Conversely, if byte values 13 and 10 have meanings other than end of line (in media types,[2] for example), then they must be encoded as =0D and =0A respectively.
To satisfy this requirement without altering the encoded text, soft line breaks may be added as desired.
This encodes the following quotation: J'interdis aux marchands de vanter trop leurs marchandises.