I came across this phrase in this r/Gintama thread about the Porori Arc mentioned in a "new season" announcement. The original poster said:
Now this could STILL turn out to be an Enchousen situation, which I am hoping, but for now all we know is that we'll be getting a pool episode rerun.
A commenter also said:
im sure its an enchousen situation
at least i hope!
What is an Enchousen situation?