title: can not install apk from email attachment to phone getting parsing error
body: <p>I have built a test android app and signed it successfully and then sent it to someone to test via email.  They click on the attachment in the email on their android phone and get a parsing error.</p>
  
  <p>They have 2.1 android  </p>
  
  <p>the test app was built using 2.2  </p>
  
  <p>would that cause an issue?</p>
  
  <p>can email attachments of apk files not be installed directly to the phone?</p>