--- a/gsm_receive_rtl.py	
+++ a/gsm_receive_rtl.py	
@@ -16,1 +16,1 @@ 
-from gnuradio import gr, gru, eng_notation, blks2, optfir
---
+from gnuradio import gr, gru, eng_notation, blocks, filter
@@ -57,1 +57,1 @@ 
-    self.converter = gr.vector_to_stream(gr.sizeof_float, 142)
---
+    self.converter = blocks.vector_to_stream(gr.sizeof_float, 142)
@@ -62,1 +62,1 @@ 
-    self.src = osmosdr.source_c(options.args)
---
+    self.src = osmosdr.source(options.args)
@@ -85,2 +85,2 @@ 
-    taps = gr.firdes.low_pass(1.0, sample_rate, 145e3, 10e3, gr.firdes.WIN_HANN)
-    self.tuner = gr.freq_xlating_fir_filter_ccf(1, taps, self.offset, sample_rate)
---
+    taps = filter.firdes.low_pass(1.0, sample_rate, 145e3, 10e3, filter.firdes.WIN_HANN)
+    self.tuner = filter.freq_xlating_fir_filter_ccf(1, taps, self.offset, sample_rate)
@@ -88,1 +88,1 @@ 
-    self.interpolator = gr.fractional_interpolator_cc(0, sps)
---
+    self.interpolator = filter.fractional_interpolator_cc(0, sps)
@@ -95,1 +95,1 @@ 
-    self.output = gr.file_sink(gr.sizeof_float, options.output_file)
---
+    self.output = blocks.file_sink(gr.sizeof_float, options.output_file)