diff --git a/src/modules/presence/README b/src/modules/presence/README
index d0f3e6fa1a8..c4ba8ca1b1a 100644
--- a/src/modules/presence/README
+++ b/src/modules/presence/README
@@ -604,12 +604,18 @@ modparam("presence", "subs_db_mode", 1)
 
 3.19. publ_cache (int)
 
-   To improve performance, the presence module holds by default a publish
-   cache that says if a certain publication exists in database. This is
-   only a list of URI + event, so it does not use much memory. The cache
-   is used when a Subscription is received to check if there is any
-   published state in database. This way unnecessary queries in presentity
-   table are avoided.
+   To improve performance, the presence module can operate in a couple of
+   modes related to how PUBLISH data is stored. If publ_cache is 0, then
+   no information is store in memory.
+
+   If publ_cache is 1, then the module keeps in memory an index of the
+   records stored in database, In this mode it keeps only the list of URIs
+   and events, so it does not use much memory. The cache is used when a
+   Subscription is received to check if there is any published state in
+   database. This way unnecessary queries in presentity table are avoided.
+
+   If publ_cache is 2, then the module keeps everything related to PUBLISH
+   requests in memory, not storing anything in the database.
 
    Setting this parameter to 0 will disable the usage of the publish
    cache. This is desirable when you have more servers sharing the same