diff --git a/Makefile.defs b/Makefile.defs
index d2671f49..c723fc45 100644
--- a/Makefile.defs
+++ b/Makefile.defs
@@ -36,7 +36,7 @@ CPPFLAGS += -D_DEBUG \
 
 #
 # ZRTP support? (see zfoneproject.com)
-WITH_ZRTP = yes
+#WITH_ZRTP = yes
 
 #
 # exclude some modules from compilation?
diff --git a/README b/README
index 18a4166d..b9cd5b08 100644
--- a/README
+++ b/README
@@ -132,6 +132,8 @@ Requirements:
  6. spandsp library for DTMF detection and PLC, optional
     (SEMS has its own implementations for both)
 
+ 7. libZRTP SDK (http://zfoneproject.com) for ZRTP, optional
+
 How to get started with SEMS:
 
   To try out SEMS, the easiest is to get a release candidate from