The newest version of Chrome is 45.0.2454.85. At least 29 security vulnerabilities were fixed in this release, and there are hints of bigger changes to come in later releases of version 45 in the associated announcement.

The change log for this version is enormous. The first reader who wants to risk a migraine to review the whole thing, and reports back to me everything that changed in this version, will win a six-pack of their favourite beer (offer expires with the next release of Chrome).

Update 2015Sep04: We now have at least a partial answer to the question. Yesterday Google published a post on the Chrome blog that explains some of the changes in Chrome 45. It’s all about performance. If you have Chrome configured to load open pages from its last session, it will now start more quickly. Chrome will now use idle time to free up memory it’s no longer using. And the expected change that prevents Flash content from auto-playing is now in effect.