Hi Hans, I noticed that recently a discrepancy in the way the prime is positioned in the presence of an index as in $f'_n$ or $f_n'$ (please see the attached PDF). However the positioning is correct in expressions such as $u^k_n$. The problem shows up only in mkiv, and as far as I can say the differnece between the results in mkii and mkiv appeared recently (unfortunately I can't say when…). %%%% begin minimal-example.tex \starttext \startbuffer[math] If for $n \geq 1$ we consider $f_{n} : {\Bbb R} \longrightarrow {\Bbb R}$ a real valued function, and $u_{n} : {\Bbb Z} \longrightarrow {\Bbb Z}$ then we denote \startformula f'_{n}(x) := \lim_{h\to 0}{f_{n}(x + h) - f_{n}(x) \over h}\qquad\mbox{and}\quad u^k_{n} := u_{n}(k) \stopformula \stopbuffer \getbuffer[math] \switchtobodyfont[times] \getbuffer[math] \switchtobodyfont[palatino] \getbuffer[math] \stoptext %%%% end minimal-example.tex