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Support Article

Duplicate days in Russian Timezone Calendar with pxDateTime



1. There are two 6th January in 2015 year Calendar.
2. There are two 1st January in 2013 year Calendar.
3. The date of 1st January 2014 is not available for selection.

Additional information:
The issue started occurring after the Time Zone change that occurred for the current time zones used in the Russian Federation October 26, 2014.

The changed moves most of existing time zones back one hour, creates three new time zones and merges two existing time zones into one new one. These time zones will not observe ‘Summer Time’ / Daylight Saving Time (aka DST)

The customer installed Microsoft Update KB2998527.
JVM was updated too by official java tz hotfix
December Cumulative Update” was installed – KB3013410

Q & A:
- can you reproduce the behaviour using the OOTB Calendar control?
Yes, we use the OOTB Calendar.

- What is the default locale of the operator?

- what is the Regional Options of the PC?

What is the operating system?

What is the browser version used?
IE 8

- Can the user see any JS errors?
No, no JS errors.

- did this Calendar used to work?
Yes, it used to work.

- what has changed since then?
We suppose it can be connected with the Time Zone Changing which we have in Russia.

Error Messages

no error message, just next dates are shifted.

Steps to Reproduce

Open Calendar from Section.
1. Choose 6th January in 2015 year Calendar.
2. Choose 1st January in 2013 year Calendar.
3. Choose 1st January in 2014 year Calendar.

Root Cause

The root cause of this problem is in a third-party product integrated with PRPC. 

It seems that this may be a behavioural change introduced with a Microsoft update (KB2998527and the December “Cumulative Update” KB3013410).

It can be proved that this issue is not PRPC specific as using simple HTML like below (after applying the said patches) will return the incorrect date until the first Wednesday of the year.

var testdate = new Date(2015,0,7);
it returns as
Tue Jan 6 23:00:00 UTC+0300 2015
Expected is
Wed Jan 7 00:00:00 UTC+0300 2015


PRPC is reflecting the incorrect UTC translation from the Windows OS, showing the day as 6th instead of 7th in the calendar.

From reviewing some Microsoft “known issues” articles, it seems that correct date time (DST changes) will be seen after end of the year.

Therefore, this is not a PRPC issue/defect which we are able to remediate in the product.

However, there is a potential short term circumvention available by using a non RTZ time zone, but staying on the same UTC value (UTC+3), until after January 7th 2015.

Published January 31, 2016 - Updated October 8, 2020

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