Please see this post in the Announcements category:
We have also released a minor update to Dorico for iPad today, bringing it (and Dorico for Education) to version 5.1.43. The main change is to temporarily remove the new contextual help feature from Dorico for iPad until the updated operation manual is available, though it also includes a couple of minor fixes. We hope to reintroduce the contextual help feature in a near future update.