diff --git a/src/gsm/libosmogsm.map b/src/gsm/libosmogsm.map
index 19ebb5b..c68cf2a 100644
--- a/src/gsm/libosmogsm.map
+++ b/src/gsm/libosmogsm.map
@@ -124,6 +124,7 @@
 gsm48_cc_msg_name;
 gsm48_cc_state_name;
 gsm48_construct_ra;
+gsm48_hdr_gmm_cipherable;
 gsm48_decode_bcd_number;
 gsm48_decode_bearer_cap;
 gsm48_decode_called;