Did you read the changeLog?
And antechinus...
We will continue to provide support in the support boards... However, we will not be patching 1.1.x any further. From now on, The recommended solution to security issues in 1.1.x is to upgrade to 2.0.x....
Ok, so let's be clear on this. The no-BS version is that in terms of security,
1.1.x is unsupported as of now. This is a change of policy over what has consistenly been claimed for years; that 1.1.x would be patched until 2.1 was stable.
That means that if an exploit for 1.1.x turns up before 2.1 is stable, which is quite possible given the pace of SMF dev, the admin of any 1.1.x site will have to turn their site upside down with a major upgrade to 2.0.x. Then, when 2.1 is stable, they will have to do it all over again if they want something up to date. 2.0.x isn't all that impressive by today's standards, and IMO has little real advantage over a well-customised 1.1.x, so this is going to be annoying. It'd be much better to just be able to go straight to 2.1, and only turn the site upside down once.
Do note that there are already other forum apps, some forked from SMF and some not, that are stable now, and have very good features, and very good migration tools. If I was still adminning a 1.1.x site, I would not be taking this announcement as an incentive to upgrade to 2.0.x, because frankly there are better options available. I would be looking at those options instead. OTOH, if I could be sure of having 1.1x patched until 2.1 is stable, I would probably be more inclined to wait for 2.1.
Bottom line is you may be shooting yourselves in the foot with this change of policy. My 2c.