I've installed Trac via the 1-click install. I too wish it was 0.12.
I tried to change the email notification to HTML (there are patches around for this) but my changed files are completely ignored. I finally discovered that although all the Trac core files are in my home directory tree, there is a shared installation in
I'm guessing that the shared installation is what gets used, and the modified files in my home dir are ignored. I'm waiting for confirmation of this from the support people, and to find out what I can do about it.
So, from what I've seen so far (not that I understand it) I don't think 1-click Trac can be upgraded for a single user, period. I hope I'm wrong. I don't know how they could even roll out 0.12 without breaking all the existing 1-click 0.11 installs. Maybe this is why it's still 0.11.
I also think that the manual installation instructions would work. They seem to bypass the 1-click (shared) installation and builds it all in your directory. This way, you could do whatever you like (at a cost).