Hi Hans, Thanks for having fixed the behavior of the prime in the latest beta release (ConTeXt version 2017.05.15 21:48). However, as you may see in the two attached PDF files, the result is still incorrect when one types for example $f_2’’(x)$, which should give the same result as $f’’_2(x)$. The correct behaviour is that obtained with mkii. Indeed one can circumvent the behaviour of the latest beta release of mkiv by using tricks such as the ones in the example code below, but this should be avoided in my opinion. The following PDF have been obtained with mkii and mkiv with the following example code. Best regards: OK %%% begin derivatives-prime.tex \starttext \startformula f''_{2}(x) = f_{2}''(x) = f^{''}_{2}(x) = f_{2}^{''}(x) % = f^{{}^{''}}_{2}(x) \stopformula As one may see the result of \type{f_{2}''(x) = } $f_{2}''(x)$ is not correct in \type{mkiv}. The following positions of the superscripts \type{(3)} are correct both in \type{mkii} and in \type{mkiv}. \startformula f^{(3)}_{2}(x) = f_{2}^{(3)}(x) \stopformula \stoptext %%% end derivatives-prime.tex