diff --git a/lib_com/options.h b/lib_com/options.h
index 91e82200a252f30b73401bc54f8db11416b0e767..1612f8c6de85c3dc52f9df0fa8eb4f968c9398b1 100644
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -93,6 +93,7 @@
 #define FIX_2411_Harmonize_TNSANALYSIS_DETECTTNSFILT    /* FhG: basop issue 2411: harmonize TNSAnalysis*_fx(), DetectTnsFilt*_fx()*/        
 #define HARMONIZE_READ_DECODE_TNS                       /* FhG basop 2389: Harm between two pairs of functions. */
 #define FIX_FLOAT_1526_DIRAC_MEM_LEAK                   /* FhG: float issue 1526: potential memory leak in DirAC handles in case of format switching */
+#define FIX_2437_HARMONIZE_ENCODERINDEX                 /* FhG: basop issue 2437 EncoderIndex_ivas_fx() and EncoderIndex_fx()*/
 
 /* #################### End BE switches ################################## */
 
diff --git a/lib_enc/ari_hm_enc_fx.c b/lib_enc/ari_hm_enc_fx.c
index d70f09062cb44e073e60628be3a0994d0c39cb58..69b355300d4678d2d1a61502036dd12c56319eca 100644
--- a/lib_enc/ari_hm_enc_fx.c
+++ b/lib_enc/ari_hm_enc_fx.c
@@ -51,6 +51,7 @@ Word16 EncodeIndex_fx(
         return 8;
     }
 }
+#ifndef FIX_2437_HARMONIZE_ENCODERINDEX
 Word16 EncodeIndex_ivas_fx(
     const Word16 Bandwidth,
     Word16 PeriodicityIndex,
@@ -79,6 +80,7 @@ Word16 EncodeIndex_ivas_fx(
         return 8;
     }
 }
+#endif // !FIX_2437_HARMONIZE_ENCODERINDEX
 /*-------------------------------------------------------------------*
  * SearchPeriodicityIndex_Single()
  *
diff --git a/lib_enc/enc_prm_fx.c b/lib_enc/enc_prm_fx.c
index e28dd0bf99392be34f6c528b1a6fc31db9afd3c2..3a4a043e3f194a9bf89dd08d86786d4354bcf8fc 100644
--- a/lib_enc/enc_prm_fx.c
+++ b/lib_enc/enc_prm_fx.c
@@ -82,7 +82,11 @@ static void enc_prm_hm_ivas_fx(
             flag = 1;
             move16();
         }
+#ifndef FIX_2437_HARMONIZE_ENCODERINDEX
         EncodeIndex_ivas_fx( flag, prm_hm[1], hBstr );
+#else
+        EncodeIndex_fx( flag, prm_hm[1], hBstr );
+#endif // !FIX_2437_HARMONIZE_ENCODERINDEX
 
         IF( EQ_16( st->hTcxCfg->coder_type, VOICED ) )
         {
@@ -1234,7 +1238,12 @@ void writeTCXparam_fx(
 
                     IF( prm[j] )
                     {
+#ifndef FIX_2437_HARMONIZE_ENCODERINDEX
                         EncodeIndex_ivas_fx( (Word16) GE_16( hm_size, 256 ), prm[j + 1], hBstr );
+#else
+                        EncodeIndex_fx( (Word16) GE_16( hm_size, 256 ), prm[j + 1], hBstr );
+#endif // !FIX_2437_HARMONIZE_ENCODERINDEX
+
 
                         flag_ctx_hm = 1;
                         move16();
diff --git a/lib_enc/prot_fx_enc.h b/lib_enc/prot_fx_enc.h
index d6b13aa6e409259de1d94a96f0661d0b3274297e..ebe4f4aa523bdf4d2f15fa693a93fb036a81a01a 100644
--- a/lib_enc/prot_fx_enc.h
+++ b/lib_enc/prot_fx_enc.h
@@ -2577,13 +2577,13 @@ Word16 EncodeIndex_fx(
     Word16 PeriodicityIndex,
     BSTR_ENC_HANDLE hBst /* i/o: bitstream handle            */
 );
-
+#ifndef FIX_2437_HARMONIZE_ENCODERINDEX
 Word16 EncodeIndex_ivas_fx(
     const Word16 Bandwidth, /* 0: NB, 1: (S)WB */
     Word16 PeriodicityIndex,
     BSTR_ENC_HANDLE hBst /* i/o: bitstream handle            */
 );
-
+#endif
 void enc_prm_side_Info_fx(
     PLC_ENC_EVS_HANDLE hPlc_Ext,
     Encoder_State *st );