Last day of current month custom function

I am looking for a custom function to make it easy to get the last day of the current month. I know there is one available called LASTDAYOFMONTH and that you can get it if you use the Crystal repository but I don't. In the past I was able to download these custom functions as dll's from BO's support site but that does not seem possible any more (I searched the SAP site high and low). There are other threads about this where article 305 from the old BO support site are being referenced but again those links does not work any more. Is there any way to download this custom function and add it to CR II release 2?