One of the most prevalent concerns that remains is React’s licensing issues.... ...the WordPress project has yet to announce its stance on the decision.

“We anticipated a decision on React around the Apache deadline (closer to now), will have more to announce about WP and Gutenberg’s approach here in the next few weeks,” Mullenweg said.

When can we expect the “more” to be announced on this issue?

For anyone interested, there’s an open GitHub issue on the Gutenberg project here - https://github.com/WordPress/gutenberg/issues/2298