cURL is required for JFBConnect. I'm not aware of PHP removing cURL from php 7.3.7 and I do not think that's true. If you're upgraded PHP, you may need to ensure that cURL was included in the upgrade.
I hope that helps, but there's not so much we can do about this requirement as cURL is how we make connections to the social networks for authentication, fetching settings and many other features in JFBConnect.
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