This is such a wonderfully symbolic act, and the way Pope Francis is expanding it from the traditional method is great, though objected to by many conservative Catholics, as this article from Chiesa notes.

An excerpt.

Washing For All. The Holy Thursday of Francis

The washing of feet now overshadows the Mass of the last supper. The pope has admitted women to the ceremony, as long as they belong to the Church. But he is pushing even farther, and is also washing the feet of Muslims

ROME, March 22, 2016 – As a reformer, Pope Francis also distinguishes himself in the liturgical field. And the day after tomorrow, on Holy Thursday, in churches all over the world there will be plain for all to see the innovation that he has introduced in the ceremony of the washing of feet, to which women too are now admitted.

As the theatre of the ceremony he will celebrate, this time Francis has chosen a refugee center, while in past years he has gone to a juvenile detention center, in 2013, to a hospice for the disabled, in 2014, and last year to a big prison. Always, therefore, to places of suffering humanity.

The day after tomorrow will therefore be the first Holy Thursday following the reform. But Jorge Mario Bergoglio has put it into practice since the first year of his pontificate, even then washing the feet of women too.

Moreover, the pope has gone beyond what is allowed by his own reform, washing the feet – more than once – of persons not belonging to the Church.

But first things first. Francis enunciated the general criterion from which he draws his inspiration for innovating in the liturgical field in the 2013 agenda-setting interview with “La Civiltà Cattolica” and twelve other magazines of the Society of Jesus:

“Vatican II was a re-reading of the Gospel in light of contemporary culture. . . Its fruits are enormous. Just recall the liturgy. The work of liturgical reform has been a service to the people as a re-reading of the Gospel from a concrete historical situation.”

The conception of the liturgy as a pedagogical act dictated by current events is an impoverishment that has understandably disconcerted the experts on this subject. Including Cardinal Robert Sarah, who was nonetheless promoted by Francis in 2014 as prefect of the Vatican congregation for divine worship.

The fact is that, after the appointment, the pope immediately told Cardinal Sarah that he had a change in mind for the ceremony of the washing of feet. A change that he made explicit and imposed in a letter to Sarah of December 20, 2014:

“I have reached the decision to make a change in the rubric of the Roman Missal. Therefore, I order that the rubric according to which the candidates chosen to receive the washing of feet be men or boys be modified in such a way as to enable the Pastors of the Church from now on to choose the candidates for the rite from among all members of the People of God.”

But it took more than a year, until Epiphany of 2016, for Sarah to issue the relative decree. Evidently not convinced of the goodness of the reform, the cardinal asked for and obtained the publication along with the decree, which he signed, of the letter with which Francis had ordered him to make the innovation, so that the real paternity of the change might be manifest.

The decree establishes that the ceremony of the washing of feet is no longer only for “men,” but more generically for those “who are chosen from amongst the people of God.” Meaning in practice “people young and old, healthy and sick, clerics, consecrated men and women and laity.”