Solution: Responds to on WhatsApp, say - NYT Crossword

I don’t know if anyone else has said it, so I will: No one uses the term “IMS” or “instant messages” anymore. The abbreviation “IM” was a product of AOL’s Instant Messaging feature, which had already substantially declined in usage by 2012. I believe the service was eliminated in 2017 or 2018. Now, people are more likely to use the terms “chat” or “message” or, if you have friends in other countries, “WhatsApp.” That’s not to say that I have a better clue for it, but if I was filling that spot, I probably wouldn’t have used it at all. Having said that, I’m not sure Ms. Carroll would have been able to do that, given the need to have 1A and 6D where they were.