If you thought I am missing 1. from Asterisk 10 in the title, this time you are wrong (I am prone to typos and I do not check my posts for faults very often).
Digium's Director of Software Engineering, Kevin Fleming has posted a lengthy article explaining the transition of Asterisk 1.10 to Asterisk 10.
"The conclusion that we’ve reached, and that we hope you’ll agree with, is that Asterisk is always going to be Asterisk, and that you don’t need a "1." prefix on the version number to be able to identify it. So, starting with the next major release, we’re going to drop the "1." completely. The next major release, which was going to be Asterisk 1.10, will now be just "Asterisk 10" and subsequent major releases will be "Asterisk 11", "Asterisk 12", and so forth.
We’ll continue with our plan to have both standard and long-term support releases of Asterisk, and we’ll update the Asterisk Project Wiki with this information as soon as the first Asterisk 10 beta goes out. In fact, this should occur very soon."
This transition also takes away Asterisk 2.0, and Kevin also explains why and how that came about.
"That has raised the question: Is this Asterisk 2.0? If not, will there ever be an Asterisk 2.0? After quite a lot of discussion, we came to the conclusion that this is not Asterisk 2.0, but that it’s also quite unlikely that there ever will be such a release; it wouldn’t be in the community’s best interests to release something that is fundamentally different (and not compatible) but still call it '‘Asterisk'.’ That then leaves the question we’ve been asked by many people: If there’s never going to be an Asterisk 2.0, "
Digium Blog
