Bug introduced in v11, fixed in v11.1

I have recently upgraded to Mathematica 11. Here is a simplified version of code that worked in v10.2:

mn = DateObject[
    DateValue[DateObject[], {"Year", "Month", "Day"}],
    TimeZone -> LocalTimeZone[]];

DateDifference[mn, mn]

The results is an error with the message:

  DateDifference::date: Expression {Gregorian,Thu 15 Dec 2016EST} cannot   
  be interpreted as a date specification.

In v10.2, the computed and expected result is 0 days.

I could not find any documentation that mentions a relevant change in DateDifference in v11.

My question is: am I missing anything? If not, how should I go about reporting this issue?

  • 4
    $\begingroup$ DateDifference[DateList@mn, DateList@mn]. But yeah, you shouldn't have to do that. $\endgroup$
    – KAI
    Dec 15, 2016 at 17:48
  • 4
    $\begingroup$ Anyway, the problem is the LocalTimeZone[]. Note that if you change it to 0, the code works. $\endgroup$
    – KAI
    Dec 15, 2016 at 17:52
  • $\begingroup$ Or use TimeZone -> $TimeZone $\endgroup$
    – Bob Hanlon
    Dec 23, 2016 at 14:19

1 Answer 1


I have reported the situation as a bug to [email protected].

  • 1
    $\begingroup$ Please edit your answer if they reply to you. $\endgroup$ Dec 23, 2016 at 14:03

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