diff --git a/lib_com/options.h b/lib_com/options.h
index a35227e091783968f01e1dc13ea4acb27796197d..a1b8b0fd33730680ef98bd354c0c144b771a854c 100644
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -154,6 +154,8 @@
 #define FIX_I13_TCX_TNS_ISSUE                           /* Issue 13: Fix reported artifacts. Bug in TNS with TCX5 */
 #define FIX_I120_INV_SQRT                               /* Issue 120: inv_sqrt() shall be used instead of 1 / sqrt() to measure the correct complexity */
 
+#define ISM_BITRATE_SWITCHING                           /* Issue 115: Support for Bitrate Switching in ISM */
+
 
 /* ################## End DEVELOPMENT switches ######################### */
 /* clang-format on */
diff --git a/lib_dec/ivas_ism_param_dec.c b/lib_dec/ivas_ism_param_dec.c
index be2b9eb350e27d198e8862c7d97c0442cc700dd6..b76c88739d533f2beae3d41f54596e07937a9414 100644
--- a/lib_dec/ivas_ism_param_dec.c
+++ b/lib_dec/ivas_ism_param_dec.c
@@ -1003,6 +1003,207 @@ void ivas_param_ism_params_to_masa_param_mapping(
     return;
 }
 
+
+
+#ifdef ISM_BITRATE_SWITCHING
+static ivas_error ivas_ism_format_bitrate_switching(
+    Decoder_Struct *st_ivas, /* i/o: IVAS decoder structure              */
+    const int16_t last_nchan_trans,  /* i  : last number of SCE channels in the bitstream  */
+    const ISM_MODE last_ism_mode,  /* i  : last ISM mode  */
+    const int16_t num_obj    /* i  : number of objects in the bitstream  */
+)
+{
+    int16_t sce_id;
+    ivas_error error;
+    int32_t element_brate_tmp[MAX_NUM_OBJECTS];
+
+    error = IVAS_ERR_OK;
+
+    ivas_ism_config(st_ivas->hDecoderConfig->ivas_total_brate, st_ivas->nchan_transport, num_obj, NULL, NULL, NULL, element_brate_tmp, NULL, NULL);
+
+    if (st_ivas->nchan_transport > last_nchan_trans)
+    {
+        /* Initialize for new bitrate */
+        for (sce_id = 0;sce_id < last_nchan_trans;sce_id++)
+        {
+            st_ivas->hSCE[sce_id]->element_brate = st_ivas->hDecoderConfig->ivas_total_brate / st_ivas->nchan_transport;
+            st_ivas->hSCE[sce_id]->hCoreCoder[0]->total_brate = st_ivas->hSCE[sce_id]->element_brate; /* dummy initialization for getting right pointers initialization of input buffers in init_coder_ace_plus() */
+        }
+
+        /* Initialize some memories */
+        for (sce_id = last_nchan_trans; sce_id < st_ivas->nchan_transport; sce_id++)
+        {
+            if ((error = create_sce_dec(st_ivas, sce_id, element_brate_tmp[sce_id])) != IVAS_ERR_OK)
+            {
+                return error;
+            }
+        }
+    }
+    else
+    {
+        /* Initialize for new bitrate */
+        for (sce_id = 0;sce_id < st_ivas->nchan_transport; sce_id++)
+        {
+            st_ivas->hSCE[sce_id]->element_brate = st_ivas->hDecoderConfig->ivas_total_brate / st_ivas->nchan_transport;
+            st_ivas->hSCE[sce_id]->hCoreCoder[0]->total_brate = st_ivas->hSCE[sce_id]->element_brate; /* dummy initialization for getting right pointers initialization of input buffers in init_coder_ace_plus() */
+        }
+
+        /* Destroy the core coder memory */
+        for (; sce_id < last_nchan_trans; sce_id++)
+        {
+            destroy_sce_dec(st_ivas->hSCE[sce_id]);
+            st_ivas->hSCE[sce_id] = NULL;
+        }
+
+    }
+
+    /* destroy the memory of hp20*/
+    if (st_ivas->mem_hp20_out != NULL)
+    {
+        for (sce_id = 0; sce_id < last_nchan_trans; sce_id++)
+        {
+            count_free(st_ivas->mem_hp20_out[sce_id]);
+            st_ivas->mem_hp20_out[sce_id] = NULL;
+        }
+        count_free(st_ivas->mem_hp20_out);
+        st_ivas->mem_hp20_out = NULL;
+    }
+
+    /* re initialize the memory of hp20 */
+    /* set number of input channels used for analysis/coding */
+
+    if (st_ivas->nchan_transport > 0)
+    {
+        if ((st_ivas->mem_hp20_out = (float **)count_malloc(st_ivas->nchan_transport * sizeof(float *))) == NULL)
+        {
+            return (IVAS_ERROR(IVAS_ERR_FAILED_ALLOC, "Can not allocate memory for HP20 filter memory\n"));
+        }
+    }
+    else
+    {
+        st_ivas->mem_hp20_out = NULL;
+    }
+
+    for (sce_id = 0; sce_id < st_ivas->nchan_transport; sce_id++)
+    {
+        if ((st_ivas->mem_hp20_out[sce_id] = (float *)count_malloc(L_HP20_MEM * sizeof(float))) == NULL)
+        {
+            return (IVAS_ERROR(IVAS_ERR_FAILED_ALLOC, "Can not allocate memory for HP20 filter memory\n"));
+        }
+
+        set_f(st_ivas->mem_hp20_out[sce_id], 0.0f, L_HP20_MEM);
+    }
+
+
+    /* Initialize the needed renderer struct and destroy the unnecessary renderer struct */
+    
+    /* select the renderer */
+    ivas_renderer_select(st_ivas);
+    ivas_output_init(&(st_ivas->hIntSetup), st_ivas->intern_config);
+    if ((st_ivas->renderer_type == RENDERER_SBA_LINEAR_ENC) && (st_ivas->ism_mode == ISM_MODE_DISC))
+    {
+        ivas_output_init(&(st_ivas->hIntSetup), st_ivas->hDecoderConfig->output_config);
+    }
+
+    if (st_ivas->ism_mode != last_ism_mode)
+    {
+        /* EFAP handle */
+        efap_free_data(&st_ivas->hEFAPdata);
+    }
+    
+    if (st_ivas->ism_mode == ISM_MODE_DISC && last_ism_mode == ISM_MODE_PARAM)
+    {
+        /* switching from ParamISM to DiscISM */
+
+        /* close the ParamISM struct */
+        if (st_ivas->hDirAC != NULL)
+        {
+            ivas_param_ism_dec_close(st_ivas->hDirAC, st_ivas->hDecoderConfig->output_config);
+            st_ivas->hDirAC = NULL;
+        }
+
+        if (st_ivas->hOutSetup.output_config == AUDIO_CONFIG_BINAURAL)
+        {
+            /* close the parametric binaural renderer */
+            ivas_dirac_dec_close_binaural_data(&st_ivas->hDiracDecBin);
+
+            /* Open the TD Binaural renderer */
+            ivas_td_binaural_open(st_ivas);
+        }
+        else
+        {
+            /* close the ISM renderer and reinitialize */
+            if (st_ivas->hIsmRendererData != NULL)
+            {
+                count_free(st_ivas->hIsmRendererData);
+                st_ivas->hIsmRendererData = NULL;
+            }
+            ivas_ism_renderer_open(st_ivas);
+        }
+
+        if (st_ivas->hOutSetup.output_config == AUDIO_CONFIG_BINAURAL_ROOM)
+        {
+            /* close the parametric binaural renderer */
+            ivas_dirac_dec_close_binaural_data(&st_ivas->hDiracDecBin);
+
+            /* Open Crend Binaural renderer */
+            ivas_crend_open(st_ivas);
+        }
+    }
+
+    if (st_ivas->ism_mode == ISM_MODE_PARAM && last_ism_mode == ISM_MODE_DISC)
+    {
+        /* switching from DiscISM to ParamISM */
+
+        /* Initialize the ParamISM struct */
+        ivas_param_ism_dec_open(st_ivas);
+
+        if (st_ivas->hOutSetup.output_config == AUDIO_CONFIG_BINAURAL)
+        {
+            /* open the parametric binaural renderer */
+            ivas_dirac_dec_init_binaural_data(st_ivas);
+
+            /* Close the TD Binaural renderer */
+            if (st_ivas->hBinRendererTd != NULL)
+            {
+                ivas_td_binaural_close(&st_ivas->hBinRendererTd);
+            }
+
+            if (st_ivas->hHrtfTD != NULL)
+            {
+                st_ivas->hHrtfTD = NULL;
+            }
+        }
+        else
+        {
+            /* Close the ISM renderer */
+            if (st_ivas->hIsmRendererData != NULL)
+            {
+                count_free(st_ivas->hIsmRendererData);
+                st_ivas->hIsmRendererData = NULL;
+            }
+        }
+
+        if (st_ivas->hOutSetup.output_config == AUDIO_CONFIG_BINAURAL_ROOM)
+        {
+            /* open the parametric binaural renderer */
+            ivas_dirac_dec_init_binaural_data(st_ivas);
+
+            /* close the crend binaural renderer */
+            ivas_crend_close(st_ivas);
+
+            if (st_ivas->hHrtf != NULL)
+            {
+                st_ivas->hHrtf = NULL;
+            }
+        }
+
+    }
+
+    return error;
+}
+#endif 
+
 /*-------------------------------------------------------------------------
  * ivas_ism_dec_config()
  *
@@ -1019,13 +1220,24 @@ ivas_error ivas_ism_dec_config(
     int32_t ivas_total_brate;
     ISM_MODE last_ism_mode;
     ivas_error error;
+#ifdef ISM_BITRATE_SWITCHING
+    int16_t last_nchan_trans;
+#endif 
 
     error = IVAS_ERR_OK;
 
     ivas_total_brate = st_ivas->hDecoderConfig->ivas_total_brate;
 
     /* store last frame ISM mode */
-    last_ism_mode = st_ivas->ism_mode;
+    last_ism_mode = st_ivas->ism_mode; 
+#ifdef ISM_BITRATE_SWITCHING
+    /* Assumes that num of input objects are constant */
+    last_nchan_trans = num_obj;
+    if (last_ism_mode == ISM_MODE_PARAM)
+    {
+        last_nchan_trans = 2;
+    }
+#endif 
 
     if ( !st_ivas->bfi && ivas_total_brate != IVAS_SID_5k2 && ivas_total_brate != FRAME_NO_DATA )
     {
@@ -1044,18 +1256,31 @@ ivas_error ivas_ism_dec_config(
 
         if ( st_ivas->ini_active_frame != 0 )
         {
+#ifdef ISM_BITRATE_SWITCHING
+            /* ISM format/bitrate switching */
+            if ((st_ivas->hDecoderConfig->last_ivas_total_brate != IVAS_SID_5k2) && (st_ivas->hDecoderConfig->last_ivas_total_brate != FRAME_NO_DATA))
+            {
+                if ((st_ivas->ism_mode != last_ism_mode) || (st_ivas->hDecoderConfig->ivas_total_brate != st_ivas->hDecoderConfig->last_ivas_total_brate))
+                {
+                    ivas_ism_format_bitrate_switching(st_ivas, last_nchan_trans, last_ism_mode, num_obj);
+                    st_ivas->nSCE = st_ivas->nchan_transport;
+                }
+            }
+#else
             /* ISM format switching */
             if ( st_ivas->ism_mode != last_ism_mode )
             {
                 /*ivas_ism_dec_reconfigure( st_ivas );*/
                 return IVAS_ERROR( IVAS_ERR_RECONFIGURE_NOT_SUPPORTED, "\n\n!!! Error: ISM format switching not supported yet!!!\n\n" );
             }
+#endif
         }
     }
     else if ( !st_ivas->bfi && ivas_total_brate == IVAS_SID_5k2 )
     {
         st_ivas->nchan_transport = num_obj;
     }
+
     switch ( num_obj )
     {
         case 1:
diff --git a/lib_enc/ivas_ism_param_enc.c b/lib_enc/ivas_ism_param_enc.c
index e515f7e204a4311457456a4b1bf68bb0ceaaf567..e8a23d6b39f512c4b02856d35f056182d7804e7b 100644
--- a/lib_enc/ivas_ism_param_enc.c
+++ b/lib_enc/ivas_ism_param_enc.c
@@ -415,20 +415,156 @@ ivas_error ivas_ism_enc_config(
 {
     ivas_error error;
     ISM_MODE last_ism_mode;
+#ifdef ISM_BITRATE_SWITCHING
+    int16_t last_nSCE;
+    int16_t sce_id, n;
+#endif 
 
     error = IVAS_ERR_OK;
 
     last_ism_mode = st_ivas->ism_mode;
+#ifdef ISM_BITRATE_SWITCHING
+    last_nSCE = st_ivas->nSCE;
+#endif 
 
     /* select ISM format mode */
     st_ivas->ism_mode = ivas_ism_mode_select( st_ivas->hEncoderConfig->nchan_inp, st_ivas->hEncoderConfig->ivas_total_brate );
 
+#ifdef ISM_BITRATE_SWITCHING
+    /* ISM format switching */
+    if ( (st_ivas->ism_mode != last_ism_mode) || (st_ivas->hEncoderConfig->ivas_total_brate != st_ivas->hEncoderConfig->last_ivas_total_brate) )
+    {
+        int32_t element_brate_tmp[MAX_NUM_OBJECTS];
+        Indice *ind_list_sce;    /* list of indices */
+        Indice *ind_list_metadata;    /* list of indices */
+
+        /* Reset and Initialize */
+        if (st_ivas->ism_mode == ISM_MODE_PARAM)
+        {
+            st_ivas->nchan_transport = 2;
+        }
+        else
+        {
+            st_ivas->nchan_transport = st_ivas->hEncoderConfig->nchan_inp;
+        }
+
+        st_ivas->nSCE = st_ivas->nchan_transport;
+        st_ivas->nCPE = 0;
+
+        ivas_ism_config(st_ivas->hEncoderConfig->ivas_total_brate, st_ivas->nchan_transport, st_ivas->hEncoderConfig->nchan_inp, NULL, NULL, NULL, element_brate_tmp, NULL, NULL);
+
+        if (st_ivas->nSCE > last_nSCE)
+        {
+            /* Reconfigure the core coders */
+            for (sce_id = 0; sce_id < last_nSCE; sce_id++)
+            {
+                copy_encoder_config(st_ivas, st_ivas->hSCE[sce_id]->hCoreCoder[0], 0);
+                st_ivas->hSCE[sce_id]->element_brate = st_ivas->hEncoderConfig->ivas_total_brate / st_ivas->nchan_transport;
+                st_ivas->hSCE[sce_id]->hCoreCoder[0]->total_brate = st_ivas->hSCE[sce_id]->element_brate; /* dummy initialization for getting right pointers initialization of input buffers in init_coder_ace_plus() */
+            }
+
+            /* Initialize the extra required memory */
+            ind_list_sce = st_ivas->hSCE[0]->hCoreCoder[0]->hBstr->ind_list;
+            ind_list_metadata = st_ivas->hSCE[0]->hMetaData->ind_list;
+
+            for (sce_id = last_nSCE; sce_id < st_ivas->nSCE; sce_id++)
+            {
+                /* Initialize the Core Coder */
+                if ((error = create_sce_enc(st_ivas, sce_id, element_brate_tmp[sce_id])) != IVAS_ERR_OK)
+                {
+                    return error;
+                }
+
+                /* prepare bitstream buffers */
+                st_ivas->hSCE[sce_id]->hCoreCoder[0]->hBstr->ind_list = ind_list_sce + (sce_id * MAX_NUM_INDICES);
+                reset_indices_enc(st_ivas->hSCE[sce_id]->hCoreCoder[0]->hBstr, MAX_NUM_INDICES);
+
+                st_ivas->hSCE[sce_id]->hMetaData->ind_list = ind_list_metadata + (sce_id * MAX_BITS_METADATA);
+                reset_indices_enc(st_ivas->hSCE[sce_id]->hMetaData, MAX_BITS_METADATA);
+            }
+        }
+        else
+        {
+            /* Reconfigure the Core Coders */
+            for (sce_id = 0; sce_id < st_ivas->nSCE; sce_id++)
+            {
+                copy_encoder_config(st_ivas, st_ivas->hSCE[sce_id]->hCoreCoder[0], 0);
+                st_ivas->hSCE[sce_id]->element_brate = st_ivas->hEncoderConfig->ivas_total_brate / st_ivas->nchan_transport;
+                st_ivas->hSCE[sce_id]->hCoreCoder[0]->total_brate = st_ivas->hSCE[sce_id]->element_brate; /* dummy initialization for getting right pointers initialization of input buffers in init_coder_ace_plus() */
+            }
+
+            /* Delete the extra memory */
+            for (sce_id = st_ivas->nSCE; sce_id < last_nSCE; sce_id++)
+            {
+                if (st_ivas->hSCE[sce_id] != NULL)
+                {
+                    destroy_sce_enc(st_ivas->hSCE[sce_id]);
+                    st_ivas->hSCE[sce_id] = NULL;
+                }
+            }
+        }
+
+        if ((st_ivas->ism_mode == ISM_MODE_PARAM) && (last_ism_mode == ISM_MODE_DISC))
+        {
+            /* Initialize the memory used by ParamISM when switch to Param ISM from Disc ISM */
+            if ((error = ivas_param_ism_enc_open(st_ivas)) != IVAS_ERR_OK)
+            {
+                return error;
+            }
+        }
+
+        if ((st_ivas->ism_mode == ISM_MODE_DISC) && (last_ism_mode == ISM_MODE_PARAM))
+        {
+            /* Reset the memory used by ParamISM when switch to Disc ISM */
+            ivas_param_ism_enc_close(st_ivas->hDirAC, st_ivas->hEncoderConfig->input_Fs);
+        }
+
+        /* destroy the memory of hp20*/
+        if (st_ivas->mem_hp20_in != NULL)
+        {
+            for (sce_id = 0; sce_id < last_nSCE; sce_id++)
+            {
+                count_free(st_ivas->mem_hp20_in[sce_id]);
+                st_ivas->mem_hp20_in[sce_id] = NULL;
+            }
+            count_free(st_ivas->mem_hp20_in);
+            st_ivas->mem_hp20_in = NULL;
+        }
+
+        /* re initialize the memory of hp20 */
+        /* set number of input channels used for analysis/coding */
+        n = getNumChanAnalysis(st_ivas);
+
+        if (n > 0)
+        {
+            if ((st_ivas->mem_hp20_in = (float **)count_malloc(n * sizeof(float *))) == NULL)
+            {
+                return (IVAS_ERROR(IVAS_ERR_FAILED_ALLOC, "Can not allocate memory for HP20 filter memory\n"));
+            }
+        }
+        else
+        {
+            st_ivas->mem_hp20_in = NULL;
+        }
+
+        for (sce_id = 0; sce_id < n; sce_id++)
+        {
+            if ((st_ivas->mem_hp20_in[sce_id] = (float *)count_malloc(L_HP20_MEM * sizeof(float))) == NULL)
+            {
+                return (IVAS_ERROR(IVAS_ERR_FAILED_ALLOC, "Can not allocate memory for HP20 filter memory\n"));
+            }
+
+            set_f(st_ivas->mem_hp20_in[sce_id], 0.0f, L_HP20_MEM);
+        }
+    }
+#else
     /* ISM format switching */
     if ( st_ivas->ism_mode != last_ism_mode )
     {
         /*ivas_ism_dec_reconfigure( st_ivas );*/
         return IVAS_ERROR( IVAS_ERR_RECONFIGURE_NOT_SUPPORTED, "Error: ISM format switching not supported yet!!!\n\n" );
     }
+#endif 
 
     return error;
 }