During COVID, OU published the following ruling on the topic, allowing it only in the most extreme cases.
- Those who are ill or have had serious exposure and must remain in isolation must not come to shul. To fulfill the Mitzvah, they should
have a kosher, hand-written Megillah in hand from which they read
audibly, either on their own or assisted by a reading heard
- The clear majority of Halachic authorities do not consider Halachically adequate a Megillah reading heard over the phone or
online. There is however a minority opinion that does allow for this,
provided that the reading is live, and not pre-recorded. Following the
Halachic principle that we may rely upon minority opinions under
extenuating circumstances, when no better option exists this minority
opinion can be relied upon.
chabad.org writes similarly
Today, with the benefit of a better understanding of how these
technologies work, the majority consensus is that one cannot fulfill
one’s halachic obligations through a telephone or microphone
(see there, footnote 2, for sources)