Hi,
If you install a signed MIDlet in the T80, no problem, but if you are configuring some NFC features in the .JAD, you will need the OTA server.
Don't worry, it starts with the user downloading the .JAD file, and then if the user agrees to download the .JAR, the URL is taken from the .JAD file. So it is easy to implement by oneself.
Greetings,
Jose