diff --git a/handbook/troggle/trogdesign.html b/handbook/troggle/trogdesign.html
index 3ace931e3..ec22748dd 100644
--- a/handbook/troggle/trogdesign.html
+++ b/handbook/troggle/trogdesign.html
@@ -33,6 +33,8 @@ is generated quite separately from the survex files and fixed-points. And it is
 <p>We have no procedure whatsoever to capture photos of cave entrances and to get them associated witht he entrance data in troggle.
 
 <p>Our former prospecting guide has died of terminal obsolescence.
+  
+  <p>Martin produced a phone app in 2023/4, but it uses a snapshot of the entrane data, not a live connection. It is also undocumented and hard to install.
 
 <p>It should be perfectly possible to convert the  entrance data as listed in the second table on
 <a href="/eastings">the troggle 'ents' page</a> into WGS84 and display it in the entrance description pages.