We will be deploying a new release of MIT App Inventor on Thursday afternoon on February 18th (2016-02-19 02:00:00 UTC). The details are in the Release Notes (DRAFT).
This release adds new Components and Features to MIT App Inventor and we will be deploying a new Companion App along with the release. However the current Companion (version 2.35) will continue to work, but new features will require an upgrade.
If you have downloaded the Companion from the Google Play Store and set it to auto-update, the update should be seamless.
However if you side loaded the Companion, or are using the emulator, then you will need to update the Companion manually. We will not be triggering an Auto Update. So people running classes on Friday the 19th will not get a surprise when they attempt to use the emulator in class. We have added a new menu choice under the Help menu (you wont see it until the release) which will permit you to upgrade your companion on the fly on a schedule of your choosing. Again, if you downloaded the Companion from the Google Play Store, and auto-update is set, you will get the upgrade without having to take any action.