Seems that PR1.2 update for N9 will also bring apps update notification feature to N9. According to Nokia developer website, the upcoming MeeGo 1.2 Harmattan update (PR 1.2) features improved support for application updates. The updated platform software will detect and announce updates to applications that are distributed through the Nokia Store.

However, there is a note for app developers as given below,

However, there are a couple of things developers need to be aware of when creating updates:

  • Do not change the name of the content item or the package name, as the new version will not be displayed as an update (however, it will be visible in the Ovi Store client).
  • Do not change the price point of the content item from free to non-free, please create a separate content item instead.