diff --git a/configure.in b/configure.in
index 9f42fcb..2bd0330 100644
--- a/configure.in
+++ b/configure.in
@@ -24,7 +24,7 @@ dnl made to the way libjack communicates with jackd
 dnl that would break applications linked with an older
 dnl version of libjack.
 dnl ---
-JACK_PROTOCOL_VERSION=4
+JACK_PROTOCOL_VERSION=5
 
 dnl ---
 dnl HOWTO: updating the libjack interface version