The “Alternative version” appears to be “faster” and doesn’t check all the other plugins by default.
Updating the ADT Plugin
To update the ADT plugin to the latest version, follow these steps:
1. Select Help > Software Updates > Find and Install.... 2. Select Search for updates of the currently installed features and press Finish. 3. If any update for ADT is available, select and install.
1. Select Help > Software Updates > Manage Configuration. 2. Navigate down the tree and select Android Development Tools
3. Select Scan for Updates under Available Tasks.