[nandemo]

Two things that are missing from the article:

1) because of this problem, the government is considering keeping Heisei for a while after the emperor steps down https://minhan.jp/4599 (in Japanese)

2) the Japanese calendar (specifically the year) is used in some official documents and formalities, but in daily life people mostly use the Gregorian calendar. If you ask a bunch of Japanese people what Heisei year is now, I bet a significant percentage of them won't remember. I've worked as a software engineer in Japan for over 10 years and I've never had to deal with Japanese calendar years.

[glandium]

The Japanese driving license expose people to the Japanese calendar years, and they are renewed every 3 or 5 years. Mine expires in 平31. So technically, it might even expire in year 1 of the new era (it expires in July).

[rtpg]

If you have to deal with larger systems that interface with finance or government orgs, you'll end up needing to work with these numbers though.

I've heard that there's not a legal framework for using Common Era dates in certain contexts, which...apparently matters? I've also heard that the gov't even has regulations for enforcing usage, but can't find a reference on that. One could think that it's merely an interface problem but if the database asks for Heisei the easiest thing is to outsource the CE -> Heisei transition to the person filling out the form.