diff --git a/configure.ac b/configure.ac
index bc256c8..d26f57e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -711,12 +711,23 @@ fi
 HAVE_CELT=false
 PKG_CHECK_MODULES(CELT, celt >= 0.7.0,[HAVE_CELT=true], [true])
 if test x$HAVE_CELT = xfalse; then
-    	AC_DEFINE(HAVE_CELT,0,"Whether CELT is available")
-	AC_MSG_RESULT(no)
-        AC_MSG_WARN([*** NetJack will not be built with celt support])
+	PKG_CHECK_MODULES(CELT, celt >= 0.5.0,[HAVE_CELT=true], [true])
+	if test x$HAVE_CELT = xfalse; then
+		AC_DEFINE(HAVE_CELT,0,"Whether CELT is available")
+		AC_MSG_RESULT(no)
+		AC_MSG_WARN([*** NetJack will not be built with celt support])
+	else
+		AC_DEFINE(HAVE_CELT,1,"Whether CELT is available")
+		AC_DEFINE(HAVE_CELT_API_0_5,1,"Whether CELT API is 0.5 API")
+		AC_DEFINE(HAVE_CELT_API_0_7,0,"Whether CELT API is 0.7 API")
+		AC_MSG_RESULT(yes (0.5))
+		NETJACK_LIBS="$NETJACK_LIBS $CELT_LIBS"
+	fi
 else
     	AC_DEFINE(HAVE_CELT,1,"Whether CELT is available")
-	AC_MSG_RESULT(yes)
+	AC_MSG_RESULT(yes (0.7))
+	AC_DEFINE(HAVE_CELT_API_0_5,0,"Whether CELT API is 0.5 API")
+	AC_DEFINE(HAVE_CELT_API_0_7,1,"Whether CELT API is 0.7 API")
 	NETJACK_LIBS="$NETJACK_LIBS $CELT_LIBS"
 fi
 
diff --git a/drivers/netjack/net_driver.c b/drivers/netjack/net_driver.c
index 998ff8b..9360d1b 100644
--- a/drivers/netjack/net_driver.c
+++ b/drivers/netjack/net_driver.c
@@ -549,13 +549,17 @@ net_driver_attach (net_driver_t *driver)
 
 	if( driver->bitdepth == 1000 ) {
 #if HAVE_CELT
+#if HAVE_CELT_API_0_7
 	    celt_int32 lookahead;
-	    // XXX: memory leak
 	    CELTMode *celt_mode = celt_mode_create( driver->sample_rate, driver->period_size, NULL );
+	    driver->capture_srcs = jack_slist_append(driver->capture_srcs, celt_decoder_create( celt_mode, 1, NULL ) );
+#else
+	    celt_int32_t lookahead;
+	    CELTMode *celt_mode = celt_mode_create( driver->sample_rate, 1, driver->period_size, NULL );
+	    driver->capture_srcs = jack_slist_append(driver->capture_srcs, celt_decoder_create( celt_mode ) );
+#endif
 	    celt_mode_info( celt_mode, CELT_GET_LOOKAHEAD, &lookahead );
 	    driver->codec_latency = 2*lookahead;
-
-	    driver->capture_srcs = jack_slist_append(driver->capture_srcs, celt_decoder_create( celt_mode, 1, NULL ) );
 #endif
 	} else {
 #if HAVE_SAMPLERATE 
@@ -596,9 +600,13 @@ net_driver_attach (net_driver_t *driver)
             jack_slist_append (driver->playback_ports, port);
 	if( driver->bitdepth == 1000 ) {
 #if HAVE_CELT
-	    // XXX: memory leak
+#if HAVE_CELT_API_0_7
 	    CELTMode *celt_mode = celt_mode_create( driver->sample_rate, driver->period_size, NULL );
 	    driver->playback_srcs = jack_slist_append(driver->playback_srcs, celt_encoder_create( celt_mode, 1, NULL ) );
+#else
+	    CELTMode *celt_mode = celt_mode_create( driver->sample_rate, 1, driver->period_size, NULL );
+	    driver->playback_srcs = jack_slist_append(driver->playback_srcs, celt_encoder_create( celt_mode ) );
+#endif
 #endif
 	} else {
 #if HAVE_SAMPLERATE
diff --git a/tools/netsource.c b/tools/netsource.c
index 2c846c0..194dde4 100644
--- a/tools/netsource.c
+++ b/tools/netsource.c
@@ -123,9 +123,13 @@ alloc_ports (int n_capture_audio, int n_playback_audio, int n_capture_midi, int
         }
 	if( bitdepth == 1000 ) {
 #if HAVE_CELT
-	    // XXX: memory leak
+#if HAVE_CELT_API_0_7
 	    CELTMode *celt_mode = celt_mode_create( jack_get_sample_rate( client ), jack_get_buffer_size(client), NULL );
 	    capture_srcs = jack_slist_append(capture_srcs, celt_decoder_create( celt_mode, 1, NULL ) );
+#else
+	    CELTMode *celt_mode = celt_mode_create( jack_get_sample_rate( client ), 1, jack_get_buffer_size(client), NULL );
+	    capture_srcs = jack_slist_append(capture_srcs, celt_decoder_create( celt_mode ) );
+#endif
 #endif
 	} else {
 #if HAVE_SAMPLERATE
@@ -162,9 +166,13 @@ alloc_ports (int n_capture_audio, int n_playback_audio, int n_capture_midi, int
         }
 	if( bitdepth == 1000 ) {
 #if HAVE_CELT
-	    // XXX: memory leak
+#if HAVE_CELT_API_0_7
 	    CELTMode *celt_mode = celt_mode_create( jack_get_sample_rate (client), jack_get_buffer_size(client), NULL );
 	    playback_srcs = jack_slist_append(playback_srcs, celt_encoder_create( celt_mode, 1, NULL ) );
+#else
+	    CELTMode *celt_mode = celt_mode_create( jack_get_sample_rate (client), 1, jack_get_buffer_size(client), NULL );
+	    playback_srcs = jack_slist_append(playback_srcs, celt_encoder_create( celt_mode ) );
+#endif
 #endif
 	} else {
 #if HAVE_SAMPLERATE