Outdated Oil

If it's just past, it's not really going to be a problem, IMO

The new Aeroshell Sport plus 4 (Red bottles) have a "Retest date" 4 years after the manufactured date. With that said, Aeroshell is SELLING this oil to its customers with dates beyond the 4 years. If Aeroshell isn't following their own "Retest date rules" then It's up to you to decide what you to do. 

Rotax's opinion on the matter is to follow the Aeroshell recommendation. 

Hi all

The recommendation from Aeroshell is to send back a sample bottle from the batch of oil in question.  They will test it and see if there is any signs of oxidation or additive breakdown.  ...well that all works well if your a warehouse and have a ton of oil on the shelf.  It was really intended for mass oil buyers who take it in drums or use a lot of oil.  Given this is not a practical what can we do?  Personally if the oil has been stored in a reasonable mater, never opened and not in hot climate extremes, out of the sun also then you should be fine.   The chance that it is bad is very rare and according to my sources you need not worry about it especially if it just at the line.  If you are perhaps 1 or 2 years over that might be different.  

Cheers