For some time now the http://cellprofiler.org/releases/ page has been in state of disarray. It seems like it is in “under construction” mode but it is been a few months now
It is all outdated and very confusing,- my personal favorite is info:
"(NOTE: Windows is still 2.1.1. Update coming soon)"
but if you are stubborn enough you can find it under Linux
Also there is section Beta (2.3.0) when it is in reality Beta of 2.2.
So it seems like there is no version 2.3 available to download.
I understand that there is a lot going on in CellProfiler right now but if you could just rearange links and update infos, it would be really help newcomers.