At the time of writing this, all branches contain the same code. Version 18.104.22.168 forms the basis of future versions. There were a few tasks and fixes that didn’t make it into 22.214.171.124 and we’ll try get those included in the 126.96.36.199 release due within the next quarter.
The 188.8.131.52 branch should be treated as alpha code and is likely to undergo many changes, some of which may break compatibility, but full details will be published when the code starts to stabilise. The only timeline currently available for a stable 184.108.40.206 release is Q1 2010.
As always your feedback is appreciated.