Summary of new Japanese era Windows updates - KB4469068

Velja za: Windows 10, version 1809, all editionsWindows 10, version 1803, all editionsWindows 10, version 1607, all editions

A new Japanese era and its associated calendar begin on May 1, 2019.

Microsoft is preparing for these changes and plans to ship updates monthly as part of our regular update cadence

These updates are intended to help customers and developers test and verify how the new Japanese era changes might impact their apps or Windows deployments. 


Windows updates

Here’s the final list of Microsoft Knowledge Base articles, listed by the Windows version they include, for the new Japanese era updates. 

You only need to install the most recent update. Each update includes all earlier updates. For the best update experience, we recommend that you have updates installed automatically on your device. Each automatic Windows update also includes the latest Japanese era updates.

For customers using Security-Only (SO) updates, refer to Changes for Security-Only update customers.


Latest updates

Knowledge Base article Windows version
KB 4494441 Windows 10, version 1809, Windows Server, version 1809 and Windows Server 2019
KB 4499167 Windows 10, version 1803 and Windows Server, version 1803
KB 4499179 Windows 10, version 1709
KB 4499181 Windows 10, version 1703 and Windows Server, version 1703
KB 4494440 Windows 10, version 1607 and Windows Server 2016
KB 4499154 Windows 10 RTM
KB 4499151 Windows 8.1 and Windows Server 2012 R2
KB 4499171 Windows Server 2012
KB 4499164 Windows 7.0 SP1 and Windows Server 2008 R2 SP1
KB 4499149 Windows Server 2008 SP2


Changes for Security-Only update customers

This section is for customers who rely only on the Security-Only (SO) updates for Windows 8.1 and earlier versions of supported Windows. Customers must continue to install each SO update as they are made available to remain protected against known security vulnerabilities. The following update can be installed by our SO customers to get all the Japanese era related fixes.

To learn more about the SO updates for Windows 8.1 and earlier, see the More on Windows 7 and Windows 8.1 servicing changes published in October 2016.


May 2019 Updates for Security-Only Customers

Knowledge Base article Windows version
KB 4499165 Windows 8.1 and Windows Server 2012 R2
KB 4499158 Windows Server 2012
KB 4499175 Windows 7.0 SP1 and Windows Server 2008 R2 SP1
KB 4499180 Windows Server 2008 SP2

New Japanese era supported products

Microsoft supports these Windows products for the new Japanese era updates.

To learn more about the Windows lifecycle, see the Windows lifecycle fact sheet.



How to test the new Japanese era artifacts on Windows

Customers and partners can choose when to add the placeholder registry entry to their systems to make preparing easier for the new Japanese era change.

Recommended test scenarios

  1. Anticipated era transition testing

This test scenario is to verify that line of business (LOB) applications work when the new era transition is set to a future date.

Let’s say that the transition date is anticipated to be 1 May 2019, so the current era is 平成 (Heisei).

Set the following registry key under

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Nls\Calendars\Japanese\Eras] registry path
"2019 05 01="2019 05 01"="令和__Reiwa_R"

  1. Active era transition testing

This test scenario is to verify that LOB applications work when the current era is set to the new era.

Let’s say that the calendar transition has already occurred on 1 May 2018 and the current era is 令和(Reiwa)".

Set the following registry key under

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Nls\Calendars\Japanese\Eras] registry path
"2018 05 01"="令和__Reiwa_R"


Test setup

Start with updating registry settings to enable different test scenarios for your LOB applications around new Japanese era change. After you back up your current registry settings, here's how to change the settings: 

Add the entry below under [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Nls\Calendars\Japanese\Eras] registry path
"2019 05 01"="令和__Reiwa_R"  


Next, here's how you test the Japanese Calendar:

  1. In the search box on the taskbar, type control panel, and then select Control Panel.
  2. Select Clock and Region, and then select Region to change the format.  

    Japanese Era additional settings view 1

  3. Change Format to Japanese (Japan).
  4. Select the Additional Settings button to open Customize Format.  

    Japanese Era customize settings

  5. Select the Date tab.  
  6. Change Calendar Type to "和暦" and select OK to apply the setting.  

New Japanese era supported features

Gannen (元年) Vs. Ichinen (1年)

In historical practice, for the first year of the era, a special character, “Gan (元),” whose Kanji character means “origin” or “beginning,” is used in place of the number “Ichi (1).” The first year “Gannen (元年)” continues until the end date of the Gregorian calendar year, December 31.

Windows now supports both “Gannen (元年)” and “Ichinen (1年)” for the first year of the era. For all the supported in-market versions of Windows from Windows 10 1809 and earlier, Gannen will be OFF by default, however, it can be enabled.

To enable Gannen, under [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Nls\Calendars\Japanese] set the InitialEraYear registry key to “元年”.

To disable Gannen, set the InitialEraYear registry key to “1”.

Windows version Default Gannen ON/OFF
19H1(Windows Insider Build) ON
Windows 10, version 1809 OFF
Windows 10, version 1803 OFF
Windows 10, version 1709 OFF
Windows 10, version 1703 OFF
Windows 10, version 1607 OFF
Windows 10 RTM OFF
Windows 8.1 / Windows Server 2012 R2 OFF
Windows7/Windows Server 2008 R2 OFF
Windows Server 2012 OFF
Windows Server 2008 OFF

VBA programming in Office that depends on OLE will support “Gannen (元年)".


When the Heisei (平成) era ends on April 30, 2019 which is Heisei (平成) 31, and the new era begins on May 1, 2019, “平成31年5月1日” becomes invalid. We have relaxed our parsers to allow the future/past dates (both Gregorian and Japanese dates) in OLE and .NET Framework, to be converted into the new Japanese era date. You will also be able to convert the future dates in Heisei to the new Japanese era once the new Japanese era name is announced. It cannot be disabled in OLE but can be disabled in .NET Framework.


Abbreviated era name

Windows will continue to support the existing abbreviation functionality. For example, for the Heisei era, the abbreviated form will continue to be “平” in Kanji and “H” in English.


The Japanese "Kanji" includes ligature/glyph that allows the era name. 平成 is represented in two Kanji characters, and ligature of this, ㍻, is represented in a single Kanji character. Here are the code points of ligature character of the existing four eras and the new era:  

㍾ (U+337E)

㍽ (U+337D)

㍼ (U+337C)

㍻ (U+337B)

令和 (U+32FF)


Collation is the assembly of written information into a standard order based on numerical order, alphabetical order or both. Currently, supported Windows versions don't support collation.


The Kanji era full name can be normalized to the Kanji ligature era name and vice versa. For example, conversion from two characters representing 平成 (Heisei) era to a corresponding ligature㍻ (Heisei) and vice-versa. However, Microsoft won't release any updates to support normalization functionality for the new era.

The Kanji era full name and the Kanji ligature era name are treated as different strings during string comparison, even if you indicate a Japanese culture-specific comparison. By design, this difference will continue for the new Japanese era.


Certain OLE functions will be updated to handle the new Japanese era. If your applications are using Date and Time functionalities from Visual Basic 6.0, VBScript, VBA, JavaScript, or ATL/MFC libraries, you'll need to apply the latest update for Windows. In some cases, and you might also need to rebuild your applications in some cases because these libraries use OLE functions.

Additional resources