My understanding is that this was the most high risk stage of the commissioning. The team are breathing a big sigh of relief. I believe multiple failures happed during testing the unfolding of the sun shield on the ground, including it tearing, resulting in multiple delays.
Fingers crossed for the next few days while they unfold the mirrors!
https://www.nasa.gov/press-release/sunshield-successfully-de...
TL;DR 139/178 release mechanisms have worked flawlessly!