Are you saying things have changed, or just that it should be labeled 2015?
Personally I wonder if data loss was addressed with the WiredTiger engine.
No. Replication still had corruption when I was dealing with WiredTiger at scale. They kept claiming to have fixed the corruption problems in each release. After that a few times, I wasn't willing to trust the claims, so I wouldn't use Mongo anywhere that I couldn't just as well use a JSON file as my data store.
And...
And it's policy here that old articles be clearly labeled as such.