Decoy24601 said:
Weird. It's odd that the website says March, then. I think they do have some leeway with this, but I also think it's up to the discretion of the person opening your packet and checking everything. I've seen people in similar situations on this forum get theirs sent back and I've seen others asked for an updated version of the form and some don't have anything happen and their application proceeds as normal.
When you look at the properties for the new form it says it was edited by CIC on March 17th, but it for sure wasn't available for download until the last week or so. Looking at CICs documentation to form changes in the past, they have offered grace periods, so for example they will likely continue accepting the older form until the end of April 2016 and then the new form must be used or face having you application sent back.
There are many examples of people using forms that are way older than this one currently is, and they never run into any issues. Also after speaking to an immigration lawyer about two months ago, he mentioned that with the changes happening in CIC, they are becoming more lenient on Family Class applications, and not returning them as much for smaller errors. Instead they are getting tougher on EE applicants apparently.