The NFL is holding the annual May owners' meetings this week, and there are some issues up for a vote. The owners will vote on Super Bowl host cities for 2019, 2020, and 2021. However, the morning saw some rule votes that tweaked instant replay. They don't cure the many issues with instant replay, but once again offer slight improvements.
The most notable is that the league will allow review for various game administration issues. This includes review of penalty enforcement (but not the specific penalties themselves), proper down, spot of a foul, and status of the game clock. Penalties remain unreviewable, so while you can challenge the spot, you can't challenge whether or not the penalty actually occurred.
Another change involves the central officiating department. During games, refs may consult with the New York office during reviews related to enforcement of penalty yardage, proper down, and status of the game clock.
Here's the full set of rules, with changes in red.