Thanks for asking.
Recently we have released the next version of Ubermenu 3.4.0 that's compatible our products. Looking at the shared screenshot I can see that you are getting update notification for Ubermenu version 3.4. You can proceed to update the plugin. Just to clear your doubt, you need to manually update the plugin by selecting the plugin and clicking on Update Plugin button.
You can take a look at version compatibility to get more information on latest compatible version of bundled and supported plugins. I am also sharing link of our theme and plugin update guide that you can refer.