3.1.1064 is the current version of DoNotTrackMePlus. However, there are problems going on with Abine, the developer, such that:
1) One of their website SSL certificates is bad, listed as being from an invalid issuer. This is unforgivable from the likes of Abine, a security company. BROKEN!
2) The new version shows up in the Safari Extensions preferences list, but WILL NOT download to install. BROKEN!
3) If you attempt to download the Safari extension from the Abine website, which is the default behavior via MacUpdate, the website inexplicably can't detect what version of Safari you're using, instead thinking it is 'Safari 0.0', like that makes any sense. Therefore, it REFUSES to let you download the extension. BROKEN!
4) Therefore, you're forced to click on their small print link labeled "Think we got your browser version wrong? Click here to start the download (at your own risk)." < --SCARY.
I can verify that after you've managed to bypass the above mess and downloaded the thing, it DOES install and DOES work going back to at least Safari version 6.1.1.
I have not verified if this new version will install and work in anything previous to Safari 6.1.1.
∑ = Hey Abine! Get your act together please!!!