At first sight, i was happy to receive yet another engine running under Android when Toga Returns had been made available by Jim Ablett.
In fact, there's no reason to oppose a growing rating list as long as enough resources are available for playing test games vs other engines.
That said, i've tested Toga Returns against its cousins. The engine proved to be a strong one, running multi threads and compatible with both time controls used in Rapidroid. It's a flawless port to Android.
Regarding the performance, below summary does not reveal any surprise. Toga 3.0 stands still with a single core while other derivatives Grapefruit, Cyclone and Toga Returns benefit from parallel search rather than better code. Actually, Toga Returns is just a tweaked Toga performing very similar to Grapefruit.
Toga "Returns" 2869 ELO overall but can't crush Grapefruit
The closed tournament was played at 300+1 time controls on Rockchip 3188 quad core downclocked to 1.0 Ghz. I've used the last 50 openings of TCEC-7. PGN games: HERE
Meanwhile, the number of Fruit derivatives wandering in Rapidroid seemed a little bit high to me and some kind of restlessness forced me jump into dusty Fruit files once again, in order to remember what was what and who forked from what. It's always complicated to understand quickly but i think what i could put together represents the overall forking tree which had started from Fruit 2.1.
Given that i may not be a qualified investigator, in case you notice something incorrect in above structure, let me know about it.
Therefore, the action which finalizes the case must be called "Rapidroid defruitized":
1) Toga Returns has nothing special to add but rating distortion. It must be ignored.
2) Grapefruit stays in because it's the strongest fork so far. I'd better keep that one.
3) Cyclone will be excluded because it's very close to Grapefruit and presents no remarkable difference.
4) TheMadPrune will be excluded because it can't play fixed time per move games and it can't use multi threads although its raison d'etre is to benefit from SMP.
5) Fruit Reloaded stays in because it's relatively new and rewritten.
6) Senpai stays. It's alive, multi threaded, above 3000 ELO and not a Fruit at all.