Kegland told me that when it has expired you can test it yourself to reset your expiration date. Fill it with water completely, try and get all the air out then connect to your gas and turn it up to 70psi / double the working pressure. If it fails it will just split and leak, if it doesn't you are good to go. Water does not compress so it will not explode, and won't use much co² either because it is full of water.
Apparently there are several tests you can do and some of them are pretty complicated and need special equipment. You can also replace the plastic container separate for less than an entire kit.
I have the fermzilla canonical and hate it. I am quite angry that I bought it RIGHT BEFORE they released the tri-clamp version. The collection container on the bottom of these fermenters does not like to come off once put on even after I heavily greased it. I have tried 5 pressure ferments in the thing and all 5 batches have come out tasting quite odd/bad. I am doing cream ales so maybe these are just not good for pressure fermentations. I am probably going to save up for the tri-clamp version or I will save up for a different pressure capable fermenter. I am also going to go back to normal fermentations for the next few batches to see if my fermenter is contaminated with something or if it was truly the pressure fermentation causing the bad flavors.
I love mine. I got a few more items with mine to be able to ferment cool and lager. Thinking about grabbing another. But I'm seriously looking at adding a stainless steel conical.