That is actually an extremely good question. Unfortunately, I haven't had a chance to update to the latest Evo ROM, or I'd offer to test it myself. Currently, running LOS, although I'll be switching back to EvoX after the new year (seriously, after having used OOS11/12/13 and LOS, EvoX seems to be the superior option for my use cases). You can easily test 911 by following the procedure laid out here (
https://www.911.gov/calling-911/frequently-asked-questions/) which involves calling your local 911 Administrator's non-emergency number and making sure it's ok to do a test at that time. If they say it's ok at that time, they will tell you exactly what to say once you've dialed 911 to make sure no one gets mad at you. Back when I installed VoIP systems for a living, I had to do this many times. It would probably not be a bad call if someone with the latest Evo were to give this a try (specifically from the lock-screen emergency dialer). That's definitely something you want to make sure is working.