I've been composing emails in python for thunderbird but I can't seem to set the reply-to field. I've tried the following with a few variations. I don't get any errors with this method, it composes just fine it just won't fill in the "reply-to" field.
'''
def composeEmail():
import subprocess
tbirdPath = r'c:\Program Files (x86)\Mozilla Thunderbird\thunderbird.exe'
to = 'sendto@somewhere.com'
subject = 'This is my subject'
mBody = 'This is the contents'
replyTo = 'replies@somewhere.com'
body = ('<html><body><h1></h1>%s<br></body></html>' % mBody)
composeCommand = 'format=html,to={},reply-to={},subject={},body={}' .format(to, replyTo, subject, body)
subprocess.Popen([tbirdPath, '-compose', composeCommand])
composeEmail()
'''