Just a heads up to anyone out there who may be performing the upgrade:
Upgrading LogInsight 4.0 -> 4.3 fails if TLSv1 is disabled! | JonKensy.com
I had to re-enable TLSv1, upgrade, and then disable again. It seems the upgrade process relies on validation of the TLSv1 protocol.
This known issue and we are working in it now.