I am not a developer but I think there are not currently any other supported providers integrated like Matrix is - but (as with the Telegram example in the screenshot) you can create a room in, for example Telegram or WhatsApp and share the URL as a Custom link from Course navigation > More > Communication (See the docs Communication (Which I assume is where you were looking anyway.)
Mary Cooch
Aportación realizada por Mary Cooch
Moodle in English -> General help -> Moodle unenroll users automatically -> Re: Moodle unenroll users automatically
de Mary Cooch -
I just edited the image for you -thanks Joost.
Moodle in Russian -> Технические вопросы -> Одобрение записи на курс преподавателем -> Re: Одобрение записи на курс преподавателем
de Mary Cooch -
Есть плагин https://moodle.org/plugins/enrol_apply, (Запись на курс одобряет администратор, а не преподаватель, но попробовать стоит)
Moodle en français -> Traduction en français de Moodle -> Limitation de la traduction pour les badges -> Re: Limitation de la traduction pour les badges
de Mary Cooch -
Peut-être y ajouter les mots de Nicolas (et ce n'est pas la première fois que je les lis...) que le code actuel ne respecte pas le "coding style" (voir ici: https://moodledev.io/general/development/policies/codingstyle#language-strings) ?