[exim] Exim mail Header

Hello ,

I have written a script which processes the incoming mails to the desired
destination.

But while checking few emails header has Subject line as mentioned below :

Subject=>=?UTF-8?B?MAHDIKSANBDKHIDBSIHDSKBDSJDSKBDSJDGSJDBSDBSJDBDJGDSDBSJDB=?=

=?UTF-8?B?fsnsmfnbmMNDSAJSDfsnfmsfnbsnNDSJAJSKnfjksnfkDsnjkDsdnDSBSHNSS==?=

I am not sure why it is coming like that while processing the mail while
reading the email in webmail or email client I am not getting such subject
format. I am getting the correct subject line in text format.

However sender is not our server I am receiving mails from other destination
and asking them to let us know what format they are using to create the
mails is not in my hand I am just reading the mails.

Is there any way to read the subject line correctly in text format as it is
appearing in the email client or webmail .

I hope I am not asking the question at the wrong place. On my server I am
using Exim as mail server.

Thank you
Pratap