Below is an expression that (for me) evaluates differently on the two most recent versions of Mathematica. Can others confirm this? It’s either a bug in v13.1.0, or my installation is faulty (which I doubt). Note: I’m running on Apple Silicon; YMMV on other processors.
Row[{First[Map[AbsoluteTime[FileDate[#]]&, {FileNames[][[1]]}]], " ", $Version}]
In both cases, the first item in the Row is a recent date expressed in seconds since the start of the last century; v13.0.1 returns it as an Integer and v13.1.0 returns it as a Real.
Earlier this month, I posted a query entitled "Function returns a list of 3 integers in v13.0.1, but raises an error in v13.1.0 by returning a list of length 5"; I was criticized (correctly) for not providing sample code, and I deleted my query as suggested. After severe pruning of the notebook (over half a megabyte in size), I believe I have found the malfunction's source, and have condensed it into a one-liner. I think the above expression will run in any notebook in any folder.
Head@ AbsoluteTime@ FileDate@ First@ FileNames[]
. I can confirm that MMA 12.3.1 on Win10-64 returnsInteger
and version 13.1.0 on Linux x86-64 (the cloud) returnsReal
. $\endgroup$