Themes.tiki.org is now using the Tiki 14 beta release. This version continues with further integration of the Bootstrap CSS framework, and other enhancements such as to trackers. The general reaction when a Tiki site is upgraded to Tiki 13 (the first release incorporating Bootstrap) or 14 is very positive, I think it's fair to say. The page generally opens up with larger text and more white space, in step with current web design and the trend to higher-resolution displays.
In parallel with the version upgrade, the content of this site is being organized, with old information that has only historical usefulness being categorized as "retired" and not available except to logged-in users.
New content about the revamped arrangement of theme-related files and about making themes for Tiki in this Bootstrap era is also being added, and will continue to be, in more detail. My own impression is that updating an old (pre-Tiki 13) theme to a current version is an easier upgrade process than has usually been the case between big-change Tiki versions. This is due to the ease of using Less variables. The procedure will be spelled out in detail shortly.
We'll also be taking a look at converting a "Bootstrap 3" theme from WordPress or Joomla, etc.to Tiki.