It looks like only the English version is shutting down. The Japanese version seems to be going strong: <a href="https://keisan.casio.jp/" rel="nofollow noreferrer">https://keisan.casio.jp/</a>
If you want a self-hosted replacement for Keisan I strongly suggest looking at Qalculate! <a href="https://qalculate.github.io/" rel="nofollow noreferrer">https://qalculate.github.io/</a><p>Qalculate even looks up relevant facts online such as when used for real time currency conversion rates, e.g. 1000 JPY/USD
(Self promotion) if people like the Casio style calculators, my app is heavily influenced by Casio’s scientific calculators. The editor works almost exactly like theirs, but it has a modern keyboard that’s optimised for touch screens. The rendering uses the LaTeX font too<p>As well, you get a few dedicated modes, like unit conversion, date calculations etc.<p><a href="https://jacobdoescode.com/technicalc" rel="nofollow noreferrer">https://jacobdoescode.com/technicalc</a>
The high precision calculator was a true gem. I have used it a few times when I needed more precision than the 64bit that Javascript gives me. Is there an alternative somewhere?