I upgraded WordPress Download Monitor from version 3.2.3 to version 188.8.131.52 and as soon as I finished the upgrade (and cleared the cache) I noticed it conflicts with Alex Rabe's popular NextGEN Gallery plugin.
DLM conflicts with NGG's legacy syntax for its SinglePic, so the following breaks:
and the error message shown reads: '[SinglePic not found]'
But this does not:
[singlepic id=18 w=450 h=693 float=center]
I am currently in the process of manually updating all my NGG legacy syntax.