diff --git a/python/receiver/fcch_detector.py b/python/receiver/fcch_detector.py
index 81438e2..9b787c2 100644
--- a/python/receiver/fcch_detector.py
+++ b/python/receiver/fcch_detector.py
@@ -36,10 +36,10 @@
 from gnuradio.filter import firdes
 import grgsm
 
-class fcch_detector(grgsm.hier_block):
+class fcch_detector(gr.hier_block2):
 
     def __init__(self, OSR=4):
-        grgsm.hier_block.__init__(
+        gr.hier_block2.__init__(
             self, "FCCH bursts detector",
             gr.io_signature(1, 1, gr.sizeof_gr_complex*1),
             gr.io_signature(1, 1, gr.sizeof_gr_complex*1),
diff --git a/python/receiver/gsm_input.py b/python/receiver/gsm_input.py
index 8c4ad51..05e323d 100644
--- a/python/receiver/gsm_input.py
+++ b/python/receiver/gsm_input.py
@@ -33,7 +33,7 @@
 import grgsm
 
 
-class gsm_input(grgsm.hier_block):
+class gsm_input(gr.hier_block2):
 
     def __init__(self, fc=940e6, osr=4, ppm=0, samp_rate_in=1e6):
         gr.hier_block2.__init__(