- Export your app using Xcode's Organizer, be sure and choose Save for Ad Hoc Deployment
- Create a folder on Dropbox and add your app's .ipa file
- Add app.plist to your folder with the following contents:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>items</key>
<array>
<dict>
<key>assets</key>
<array>
<dict>
<key>kind</key>
<string>software-package</string>
<key>url</key>
<string>https://dl.dropboxusercontent.com/s/0zo8hkd3pfifiiu/APP_NAME.ipa</string>
</dict>
</array>
<key>metadata</key>
<dict>
<key>bundle-identifier</key>
<string>com.example.APP_NAME</string>
<key>bundle-version</key>
<string>1.0</string>
<key>kind</key>
<string>software</string>
<key>title</key>
<string>APP_NAME</string>
</dict>
</dict>
</array>
</dict>
</plist>
- Right click the .ipa file after it's uploaded to Dropbox and choose Share Dropbox Link. Replace the link in the .plist file and convert it from https://www.dropbox.com/s/2t6kra9wt80nhe1/APP_NAME.ipa?dl=0 to https://dl.dropboxusercontent.com/s/2t6kra9wt80nhe1/APP_NAME.ipa (also replace APP_NAME with whatever)
- Then get a Dropbox shared link for the app.plist and send it to someone like this: itms-services://?action=download-manifest&url=https://dl.dropboxusercontent.com/s/a2klje76r4mhife/app.plist
OTA app distribution must be done over https as of iOS 7—by using Dropbox shared links you can get that for free.