It's possible to add the three tickets fileds (Criticality, Urgency, Priority ) on the activity.

It is possible 🙂
but it won't be done in the community edition 🙁

These fields are really dedicated to Tickets Management.
And Activities already have a priority field, wich has impact to planning calculation.

thanks for your answer.
but I really need criticality on activity, the 2 others fields are not very important for me.
the only solution is to create custom class for activity and add the field criticality in the activity table ?

Thanks

Yes :
Add idCriticallity on table activity, format int(12).
Add idCriticallity field on class Activity.php.