Laws of Azaan

Reciting "Salloo fi buyootikum" in place of "Hayya alas Salaah" and Hayya alal Falaah"

Q: Nowadays, masaajid being closed, azaan is a bit modified. In place of Hayya alas Salaah, Hayya ala Falaah, it is said, Salloo fi buyutikim and salloo fi rihalikum. Is it permissible to change azaan and was it done in the era of Sahaabah (radhiyallahu anhum)? How should we reply to these words?