30 day battle records
Only, making it compatible with current server and rewrite the protocol for lightning fast uploads at the same time implies 2 protocols.
The second protocol only becoming useful after a new server with the new protocol appears. This protocol rewrite will probably only work if a new server is written at the same time.
Compatibility with Distributed Robocode will imply in a third protocol, but can be done. Only I never used Distributed Robocode.
Multi-threading is nice. This was the reason I tried to build a custom client myself in the past. Only I never managed to isolate classpaths between engine instances. One problem with multi-threading is OutOfMemoryErrors tend to crash all threads, making it harder to recover (i.e. one thread is saving results while another throws OOME, crashing everything and corrupting files).