1. Where a gatekeeper provides number-independent interpersonal communications services that are listed in the designation decision pursuant to Article 3(9), it shall make the basic functionalities of its number-independent interpersonal communications services interoperable with the number-independent interpersonal communications services of another provider offering or intending to offer such services in the Union, by providing the necessary technical interfaces or similar solutions that facilitate interoperability, upon request, and free of charge.

2. The gatekeeper shall make at least the following basic functionalities referred to in paragraph 1 interoperable where the gatekeeper itself provides those functionalities to its own end users:

(a) following the listing in the designation decision pursuant to Article 3(9):

(i) end-to-end text messaging between two individual end users;

(ii) sharing of images, voice messages, videos and other attached files in end to end communication between two individual end users;

(b) within 2 years from the designation: