The only place I see it is within the Akeeba Backup dashboard, but if I don't happen to go there, then I don't realise there is a new version of Akeeba Backup available.
Other plugins show a notification on the plugins page, and increment a counter which appears alongside the 'Plugins' menu item in the left hand black column.
Incidentally, the new version availability doesn't show up in Watchful.li for the site either.
|WordPress version (in x.y.z format)||4.8.2|
|PHP version (in x.y.z format)||7.1.9|
|Akeeba Backup version (x.y.z format)||2.3.3|