diff --git a/include/patty/ax25.h b/include/patty/ax25.h
index 9cf4d6a..9f3281b 100644
--- a/include/patty/ax25.h
+++ b/include/patty/ax25.h
@@ -8,6 +8,11 @@
 
 #define PATTY_AX25_MAX_HOPS 8
 
+enum patty_ax25_version {
+    PATTY_AX25_OLD,
+    PATTY_AX25_2_0
+};
+
 enum patty_ax25_proto {
     PATTY_AX25_PROTO_UNKNOWN       = 0x00,
     PATTY_AX25_PROTO_ISO_8208      = 0x01,
@@ -38,7 +43,11 @@ typedef struct _patty_ax25_address {
 
     int ssid;
     int last;
-    int repeated;
+
+    union {
+        int c;
+        int repeated;
+    };
 } patty_ax25_address;
 
 typedef struct _patty_ax25_frame {
@@ -49,6 +58,7 @@ typedef struct _patty_ax25_frame {
     int hops;
     int repeated;
 
+    enum patty_ax25_version    version;
     enum patty_ax25_frame_type type;
 
     uint8_t control;
diff --git a/include/patty/ax25/macros.h b/include/patty/ax25/macros.h
index 90d6c65..6243032 100644
--- a/include/patty/ax25/macros.h
+++ b/include/patty/ax25/macros.h
@@ -10,6 +10,9 @@
 #define PATTY_AX25_ADDRESS_SSID_NUMBER(c) \
     ((c & 0x1e) >> 1)
 
+#define PATTY_AX25_ADDRESS_SSID_C(c) \
+    ((c & 0x80) == 0x80)
+
 #define PATTY_AX25_ADDRESS_SSID_REPEATED(c) \
     ((c & 0x80) == 0x80)
 
diff --git a/src/Makefile b/src/Makefile
index 1c9c224..4707684 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -7,7 +7,7 @@ CC		= $(CROSS)cc
 CFLAGS		= $(CGFLAGS) -fPIC -Wall -O2 -I$(INCLUDE_PATH)
 LDFLAGS		=
 
-HEADERS		= kiss.h ax25.h
+HEADERS		= kiss.h ax25.h ax25/macros.h
 OBJS		= kiss.o ax25.o test.o
 
 PROGRAM		= test
diff --git a/src/ax25.c b/src/ax25.c
index be04aa3..585de76 100644
--- a/src/ax25.c
+++ b/src/ax25.c
@@ -49,9 +49,9 @@ static ssize_t frame_decode_address(patty_ax25_address *address, void *data, off
     /*
      * Now, unpack the data from the SSID field.
      */
-    address->repeated = PATTY_AX25_ADDRESS_SSID_REPEATED(ssid);
-    address->ssid     = PATTY_AX25_ADDRESS_SSID_NUMBER(ssid);
-    address->last     = PATTY_AX25_ADDRESS_OCTET_LAST(ssid);
+    address->c    = PATTY_AX25_ADDRESS_SSID_C(ssid);
+    address->ssid = PATTY_AX25_ADDRESS_SSID_NUMBER(ssid);
+    address->last = PATTY_AX25_ADDRESS_OCTET_LAST(ssid);
 
     return 7;