This release fixes, among others, a high memory consumption problem in i3 4.5. The issue, as explained by Michael, is a result of a human mistake in the release process. For full details of a bug report, see this. The new release fixes the problem, as well as, introduces a few other changes.
Feel free to use my SlackBuild script to build the latest stable release of i3 including all the bugfixes. The builds for Slackware 14 and the -current branch are available here: