As we communicated in January, support for NPAPI (Netscape Plug-in API) will be discontinued with the release of Chrome 42 this month. Google will unpublish extensions requiring NPAPI plugins from the Chrome Web Store as well. Because not all plugin vendors will be able to move to alternate technologies by the release of Chrome 42, Google will provide an override for advanced users (via chrome://flags/#enable-npapi) and enterprises (via Enterprise Policy) to temporarily re-enable NPAPI to give mission-critical plugins more time to make the transition.
In September 2015, Google will remove the override and NPAPI support will be permanently removed from Chrome. Installed extensions that require NPAPI plugins will no longer be able to load those plugins.
A few of the major plugins affected are Java, Silverlight and Flash; affected applications include Business Objects, WebNow, Planview and Blue Jeans. Note that this is not a complete list and there may be other applications affected as well. Keep in mind that you can use a different browser if you experience issues.
For more information, see The Final Countdown for NPAPI.