SEBA-379 Document fabric-crossconnect service

Change-Id: I026b881b2e0b896d0b73e688a4c09a979363bf4f
diff --git a/Dockerfile.synchronizer b/Dockerfile.synchronizer
index 5a07cdc..72d5765 100644
--- a/Dockerfile.synchronizer
+++ b/Dockerfile.synchronizer
@@ -16,7 +16,7 @@
 
 # xosproject/fabric-crossconnect-synchronizer
 
-FROM xosproject/xos-synchronizer-base:2.1.22
+FROM xosproject/xos-synchronizer-base:2.1.24
 
 COPY xos/synchronizer /opt/xos/synchronizers/fabric-crossconnect
 COPY VERSION /opt/xos/synchronizers/fabric-crossconnect/