diff --git a/iocsh b/iocsh
index 2975fa9..5e64815 100755
--- a/iocsh
+++ b/iocsh
@@ -184,10 +184,11 @@ then
         EPICS_BASE=$(\ls -1vrd $EPICS/base-$BASE/bin/{${EPICS_HOST_ARCH},${EPICS_HOST_ARCH%_64}} 2>/dev/null | head -n1)
         if [ -z "$EPICS_BASE" ]
         then
-            # find highest (requested) EPICS version that supports our architecture (or its 32 bit version)
+            # find highest (requested) 3-part-numeric EPICS version that supports our architecture (or its 32 bit version)
             # ignore all versions listed in ignore file
             EPICS_BASE=$(eval \ls -1vrd $EPICS/base-$BASE*/bin/{${EPICS_HOST_ARCH},${EPICS_HOST_ARCH%_64}} 2>/dev/null \
                 $(test -f $EPICS/ignore && sed < $EPICS/ignore ':b;$!N;s/[[:space:]]/|/;tb;s/\./\\./g;s/.*/|grep -Ev \x27&\x27/g') \
+                | grep -E '/base-[0-9]+\.[0-9]+\.[0-9]+/' \
                 | head -n1)
         fi
     fi