chg: [decay] update requirement for Gerard

a.5-decaying-indicators/content.tex

@@ -29,6 +29,16 @@
     \end{itemize}
 \end{frame}
 
+\begin{frame}
+\frametitle{Decaying Features in MISP}
+        \begin{itemize}
+        \item Starting from MISP 2.4.116, the decaying feature is available
+        \item Don't forget to update the decay model and enable the ones you want
+        \item The decaying feature has no impact on the information in MISP, it's just an overlay to be used in ther user-interface and API
+        \item Decay strongly relies on taxonomies and sighting, don't forget to review their configuration
+        \end{itemize}
+\end{frame}
+
 \begin{frame}
     \frametitle{\textit{Sightings} - Refresher}
     \textit{Sightings} add temporal context to indicators.