(1) by handing the notice or copy to the beneficiary personally, or to his guardian, or attorney of record; or
(2) by sending it by registered mail with return receipt requested to such beneficiary, or his guardian or attorney of record, at the last known address of the addressee.
Any beneficiary or the trustee may petition the court for a hearing on any intermediate account, and the holding of such a hearing shall be in the discretion of the court. In the case of the third intermediate accounting and every three years thereafter the trustee shall apply to the court for a hearing on and approval of all unapproved accounts and shall give each known beneficiary written notice of such application 20 days before the return day thereof, in the manner prescribed for the delivery of the copy of the account. The return day of the application for a hearing on an intermediate accounting shall be at least 20 days after the latest account was filed. The notice by the trustee of the application for a hearing on and approval of the account shall inform the beneficiaries of the amount of commissions or other compensation to be requested by the trustee on such hearing, and the amount of other fees which the court will then be requested to allow.