diff --git a/software/gr-caribouLite/lib/caribouLiteSource_impl.cc b/software/gr-caribouLite/lib/caribouLiteSource_impl.cc
index 0212148..de7115b 100644
--- a/software/gr-caribouLite/lib/caribouLiteSource_impl.cc
+++ b/software/gr-caribouLite/lib/caribouLiteSource_impl.cc
@@ -57,7 +57,7 @@ namespace gr {
                                                 bool provide_meta)
                         : gr::sync_block("caribouLiteSource",
                           gr::io_signature::make(0, 0, 0),
-                          gr::io_signature::make(1, 2, {sizeof(gr_complex), sizeof(uint8_t)})
+                          gr::io_signature::make2(1, 2, sizeof(gr_complex), sizeof(uint8_t))
                           )
         {
             detectBoard();