It would be very helpful if RE would allow a setting to be toggled to prevent a gift from being posted into a previous fiscal year. I would be fine with a dialogue box that allows you to override the error or even just a warning to let you know that you're posting a gift to a prior fiscal year. Mistakes happen and it would be nice to catch these on the front end instead of having to correct the error with an adjustment.
This should be happening for you if you are putting to and from dates on the fund records.
I think this already happens? At least in our database. Once one fiscal year ends, are you making appeals inactive? If so, you should get a pop up that says the gift date is out of appeal range.