Law 39/2015:
Article 44. Unsuccessful notification.
"When those interested in a procedure are unknown, the place of the notification is unknown or, once it has been tried, could not be practiced, the notification must be made by means of a published announcement in the "Official State Gazette".
Likewise, in advance and on an optional basis, the administrations may publish an announcement in the official bulletin of the Autonomous Community or of the province, on the edict board of the City Council of the last address of the interested party or of the consulate or section. consular officer of the corresponding embassy.
Public administrations may establish other complementary forms of notification through other media, which do not exclude the obligation to publish the corresponding notice in the "Official State Gazette". "
Article 45. Publication.
"4. Without prejudice to the provisions of article 44, the publication of acts and communications that, by legal or regulatory provision must be carried out on a bulletin board or edict, is understood to be completed by its publication in the corresponding official newspaper. "
Third additional provision. Notification by means of an announcement published in the "Official State Gazette".
"1. The" Official State Gazette "must make available to the various public administrations an automated system of electronic submission and management for the publication of the notification notices provided for in article 44 of this Law and in This additional system, which must comply with the provisions of this Law and its implementing regulations, must guarantee the speed of publication and its correct and accurate insertion, as well as the identification of the sending body.
2. In administrative procedures that have specific regulations, if the cases provided for in article 44 of this Law apply, the practice of notification must be carried out, in any case, by means of an announcement published in the “Bulletin Official of the State ”, without prejudice to the fact that previously and on an optional basis it may be done in the manner provided for by the specific regulations mentioned.
3. The publication in the Official State Gazette of the advertisements referred to in the two preceding paragraphs shall be effected without any financial consideration by those who have requested it. "
YOURS (via EACAT)