Starting from version 0.7, every time when a new version of any QAPlug plugin will be available, you will be notified about it by a small window in the right corner of your IntelliJ IDEA (please see picture below).

You can also press plugin updates notification label located on the status bar, which allows you to update plugins immediately.

The same information is presented in QAPlug settings window as it is shown on the picture below.