Setpos in previous versions supported non-hole number for the setpos method. In 4.0.0 a non-whole number generates message:
Error 88.907: Argument 1 must be in the range -2147483648 to 2147483647; found ".5"
There is also to mention of whole numbers in the document. Attached is testcase.
I will have to back off 4.0.0 until fixed.