The official docker image is still at v0.11 and was last updated in 2016. It looks like maybe trunk is at 0.12, but, as far as I can tell, that a rolling release. My prosody install is too important to go with a rolling release.
Both the alternatives that they point to are similarly old;
That would probably the best practice. But as another post said, I don't trust myself (and I lack the skills, although that's pretty lame excuse).