Well...
Sphere 1.0 is a long way off, the 99z* versions aren't usable for a live shard yet to due to bugs/incomplete code, so everyone is stuck (and has been stuck for years) on 55i.
There are huge (300-400 player) shards running 55i and the injection exploits are just pounding them into the ground. Zorm created a DLL to patch 55i in memory to fix these bugs... then he added Kell's KPatch (a few new triggers, some new commands) into it, and ended up with a very nice "fix" for 55i for people to use. Unfortunately, this fix was coded in assembly the long hard way. Kell came back from his year long vacation and saw what Zorm was doing, so he joined up. They created a sourceforge project for it "Sphere Evo" not too long ago. Maybe three days later I showed the URL to it to Westy (one of the sphere coders that's been in retirement quite some time). He felt sorry for them and their efforts and gave us the 55i source to work with that instead of the assembly nightmare they were doing. I'm no programmer, I just have the source for kicks I suppose
Thus was born Sphere 55i Revision 1. A war broke out when the "terms" of having the 55i source were disputed. To make a long story short, the original sphere devs wanted only bugs fixed in 55i and no new features added... wanted it to be nothing more than a lifeline for shards waiting on 1.0... a war that very nearly caused Westy to revoke rights to even HAVE the source. Looks like features will be allowed though, as it's pretty obvious some of the shards on 55i for the last 2 years have no intentions of upgrading to 1.0 when it does finally come out.
The intentions were never to split sphere in half, we're being very careful not to do that. I don't want an UOX-style split in the sphere community. I think there's plenty of users to go around for both versions. Either way.. it's all still sphere