Issue with Circumflex character in email

I am working with French language email processing using PHP and desktop client. I have an issue with a circumflex around [ o: ô ].

My application runs in a following fashion:
a. A desktop client software made in WinDev composes an email, including the circumflex characters (o hat)
b. It being unicode email, I first url encode the content, then base64 encode and trasfer to the remote server for email processing.
c. Remote server reverses the string and sends the email.

Everything else is okay, except the single character: O with hat. After some analysis, I have found that, it is not a unicode character at all. It has the corresponding ASCII Value: 244.

Some applications like windows notepad (alt+0244: ô) and command prompt (alt+244: ⌠) show different characters. Save the notepad file, and open it again, your character will be replaced with a new one.

At the PHP end, the character is not received correctly, it is a single byte character in the Unicode stream, which makes it look different and cause the email look bad.

Any suggestions?
ôô⌠ôô ôô⌠ôô ôô⌠ôô ôô⌠ôô ôô⌠ôô

Yes 'tis.

Have you (can you) insert character references like this?

& #244; (remove space)