For now the latest 0.13.0-beta7 is based on the latest Chromium stable 48. As we are approaching the final release, and Chromium 49 stable will be released at Mar. 8 by estimation, we're going to release 0.13.0-rc1 with Chromium 49 in the following days. Node.js will be updated to 5.7.0.
RC1 will focus on the rebase to Chromium 49 and Node 5.7.0. After that we'll continue to fix reported issues. The final version of 0.13.0 is expected to be released within Chromium 49 lifetime (before Chromium 50 release).
As we follow upstream releases closely, the release plan tries to coordinates our 0.13.0 development and upstream release cycles. From now on, our target is to release a (major) new version of NW for every Chromium stable release, unless it's blocked by v8 API incompatibility between Chromium stable and Node.js.