The rabbis of an organization called "Igud Chachmey HaMaarav", which seems to be an organization of rabbis of Moroccan descent, has issued an interesting psak very relevant to the upcoming Pesach.

The question posted to the group of rabbis was because of the CoronaVirus, elderly people will not be able to join their children and grandchildren at the Pesach seder this year and will have to celebrate the seder alone. The question is if the families could set up a ZOOM connection to video broadcast the seder between the family and the elderly grandparents, thus allowing the families to celebrate together and not be alone. Obviously no actual action would be taken during the holiday to work the system - the screens would be set up and activated in advance in each house before the holiday begins and be ready and waiting for them to just sit down at the seder and begin. Would this be allowed in this time of need and emergency?

The group of rabbis issued a psak in response that because of the tense situation we find ourselves in, it would be allowed to conduct the seder jointly using ZOOM video conferencing as a medium. They stress that the allowance is for this year alone due to the situation. Adding to that is the seder night being one that facilitates many people performing mitzvas they would otherwise not do simply if not for the connection with their grandparents, and that is very important.

Further, it is necessary to lighten the burden and stress on the elderly and infirm, and to give them purpose and motivation to avoid depression and weakness but to fight to continue.

The letter is signed by 14 rabbis, some of whose names I am familiar with, and most of whom I have never heard of, and are very significant rabbis and poskim.
source: Kipa

I am surprised. This sort of takes the "heter kiruv" to an extreme. I get the extenuating circumstances, and I am still surprised by the psak. Also, I was surprised to learn that, according to the letter, sefardi rabbonim generally allow one to turn on lights and activate electricity on yomtov. I did not know that.

As to the issue itself, using ZOOm would require a paid subscription. The free account cuts off after 40 minutes or so, so that would not even make it to the seder if you turn it on before the holiday begins. The only way would be to use a paid subscription. Or you can use a different platform like skype or Google Meet or something else.

Another issue would be the concern of someone trying to adjust the screen or turn it back on if the connection gets cut off, or if sound quality drops. If turning on electricity is not a concern for sefardim, it might not be an issue though that is not what the psak allowed - the psak only allowed turning it on before chag, not during chag. Ashkenazim relying on this would have a problem in such a situation, and the concern that this might happen could be enough of a reason to not allow it.

ZOOM also might not be the best platform for this because of the way it works, with the screen adjusting between the cameras based on who is talking. So when a person talks at the seder, he or she will be causing the screen to adjust and something in zoom to activate and change. Again, a different platform might not have this issue. And again, for sefardim this might be less of a concern.

UPDATE:
since the letter was published yesterday evening, two of the rabbis signed on it have backed out, each for his own reason. One because he says it was not supposed to be published yet but he had expected it to be sent to gedolim for approval, and since it was not he backs out. The other because it was not supposed to be published publicly but to be kept private and only used in the most extreme situations upon personal consultation with the rabbi. The cat may already be out of the bag, but we'll see how this progresses.