For those users who live backwards in time, here is information about downgrading to Emacs version 24.5. We hope you will enjoy the greater simplicity that results from the absence of many Emacs 25.1 features.
setfmust be called with an even number of arguments has been removed. You can now call them with an odd number of arguments, and Emacs will helpfully supply a
nilfor the missing one. Simplicity rules!
EMACSenvironment variable, as they should, to indicate that the subprocess is run by Emacs. This is so packages that took years to learn how to work around that setting could continue using their code to that effect.
save-excursionform saves and restores the mark, as expected. No more need for the new
save-mark-and-excursion, which has been deleted.
substitute-command-keysleaves the quote characters alone. As you move back in time, Unicode support becomes less and less important, so no need to display those fancy new quotes the Unicode Standard invented.
[:alnum:]will match any character with a word syntax, and
[:print:]will match any multibyte character, including surrogates and unassigned codepoints. Once again, this is in line with diminishing importance of Unicode as you move back in time.
pcaseform was significantly simplified by removing the UPatterns
app. To further simplify this facility, we’ve removed
pcase-defmacro, since we found no need for letting Lisp programs define new UPatterns.
cursor-sensor-functions, replacing them by the much simpler
point-leftproperties. The latter are implemented on a much lower level, and therefore are better integrated with user expectations. For similar reasons,
cursor-sensor-modewere removed; use the hook variable inhibit-point-motion-hooks which is no longer obsolete.
pipeconnection type. Redirecting
stderrof a subprocess should be done with shell facilities, not by Emacs.
string-collate-equalpwere removed. Their locale-independent counterparts
string-equalare so much more simple and yield predictable results that we don’t see any situation where the locale-dependent collation could be useful in Emacs. As result, the ls-lisp.el package sorts files in a locale-independent manner.
current-time-string, no longer accept an optional zone argument. If you need to change the current time zone (why?), do that explicitly with