Handling a new era in the Japanese calendar in .NET
https://blogs.msdn.microsoft.com/dotnet/2018/11/14/handling-a-new-era-in-the-japanese-calendar-in-net/

>Since the new era name has not been announced, you can use question marks as a placeholder. For the native full and abbreviated name,
>you can use the FULLWIDTH QUESTION MARK (U+FF1F), and for the English full and abbreviated name, you can use the QUESTION MARK (U+003F). For example:

>[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Nls\Calendars\Japanese\Eras]
>"2019 05 01"="？？_？_??????_?"

https://msdnshared.blob.core.windows.net/media/2018/08/heisei-era.png