ActiveAdmin 4 support?

[Dysp]

Because date_n_time_picker_activeadmin >= 0.1.3 depends on activeadmin >= 3.2.5, < 4.A
  and date_n_time_picker_activeadmin < 0.1.3 depends on activeadmin >= 2.9, < 3.A,
  activeadmin >= 2.9, < 3.A OR >= 3.2.5, < 4.A is required.
So, because Gemfile depends on activeadmin = 4.0.0.beta15,
  version solving has failed.