Birthday Hub for W10 universal and WP8.1 is gone free without any ads.
The app does not only remind you on todays birthday, it also reminds you about missed anniversaries on previous days if your PC or notebook was off on the day of the anniversary. In this situation the calendar doesn’t break the silence.
The previous versions have been available as trial and paid full version for $1.99.
Now the WP8.1 version is completely free and the W10 universal version is free with a Pro version in-app purchase as upgrade.
The Pro in-app purchase in the W10 version is free for a few days and later it will be €/$ 1.99.
All important features are available in the free version and the Pro version features are nice to have features (i.e. theming and OneDrive backup) and for supporting the further developing.