This is a follow-up question to How to replace the word "Chapter" for appendix items with "Appendix" in book using titlesec.
I've tried \begin{appendices} ... \end{appendices} and, whilst it does not show any errors, the word Chapter appears for Appendix items in TOC.
Change to \appendix (and do nothing else) and the word Chapter changes to Appendix.
I am just surprised because the former would appear to be a more precise control.
\begin{appendices}...\end{appendices}(to say all the truth it was\begin{appendix}...\end{appendix}) with\appendixsimply to apply\g@addto@macroto\appendix. You were not using any feature of that environment. – karlkoeller Mar 07 '15 at 18:28appendicesenvironment in my answer at your previous question. – karlkoeller Mar 07 '15 at 18:41