Protocol from September 2, 2015

License

GPL V3.0 selected as candidate. Check whole license for any inadequate regulations.

Raspberry Pi supports Java and Java Native Interface (JNI). Does not support JavaFX (no native support with Oracle Java)

Model-View-Presenter with Dolphin-Smalltalk version. Use of Interfaces highly demanded (for exchangeability)

Logging: own implementation or use of APIs (recommended); Apache as good option
User-Identifier: implementation to be specified
Server-Password: undefined how to be secured
User-Management: a) public keys dependent of underlying security system b) Profile-Pic: read pixeldata, transmit as byte-array to server; possible restrictions: max 256*256px/"standard-header" with 8-byte as size)
Data-transfer: no storage needed (within DBMS) -> "directly" transmitted

DBMS to be selected. Object-relational mapper (ORM) with JPA-standard used for easier implementation of DB-requests. Power of JPA to be looked up.

Restart: Interval & Weekday
Maintenance: Interval scheduling (dependent of last maintenance/server start) or absolute time
Update-Scheduling: Time & Date
Information to all users via popup or similar; broadcast needed.