diff --git a/libisofs/filters/external.c b/libisofs/filters/external.c
index 36dddb7..0f7bba5 100644
--- a/libisofs/filters/external.c
+++ b/libisofs/filters/external.c
@@ -46,11 +46,6 @@ typedef struct
     int out_eof;
     uint8_t pipebuf[2048]; /* buffers in case of EAGAIN on write() */
     int pipebuf_fill;
-
-#ifdef Libisofs_extf_old_behavior_bit_0
-    int is_0_run;
-#endif
-
 } ExternalFilterRuntime;
 
 
@@ -72,11 +67,6 @@ int extf_running_new(ExternalFilterRuntime **running, int send_fd, int recv_fd,
     o->out_eof = 0;
     memset(o->pipebuf, 0, sizeof(o->pipebuf));
     o->pipebuf_fill = 0;
-
-#ifdef Libisofs_extf_old_behavior_bit_0
-    o->is_0_run = 0;
-#endif
-
     return 1;
 }
 
@@ -128,26 +118,10 @@ int extf_stream_open_flag(IsoStream *stream, int flag)
         return ISO_NULL_POINTER;
     }
     data = (ExternalFilterStreamData*)stream->data;
-
     if (data->running != NULL) {
         return ISO_FILE_ALREADY_OPENED;
     }
 
-#ifdef Libisofs_extf_old_behavior_bit_0
-    if (data->cmd->behavior & 1) {
-        if (iso_stream_get_size(data->orig) == 0) {
-            /* Do not fork. Place message for .read and .close */;
-            ret = extf_running_new(&running, -1, -1, 0, 0);
-            if (ret < 0) {
-                return ret;
-            }
-            running->is_0_run = 1;
-            data->running = running;
-            return 1;
-        }
-    }
-#endif /* Libisofs_extf_old_behavior_bit_0 */
-
     if (data->size < 0 && !(flag & 1)) {
         /* Do the size determination run now, so that the size gets cached
            and .get_size() will not fail on an opened stream.
@@ -260,11 +234,6 @@ static
 int extf_stream_close(IsoStream *stream)
 {
     int ret, status;
-
-#ifdef Libisofs_extf_old_behavior_bit_0
-    int is_0_run;
-#endif
-
     ExternalFilterStreamData *data;
 
     if (stream == NULL) {
@@ -276,34 +245,18 @@ int extf_stream_close(IsoStream *stream)
         return 1;
     }
 
-#ifdef Libisofs_extf_old_behavior_bit_0
-    is_0_run = data->running->is_0_run;
-    if (!is_0_run) {
-#endif
+    if(data->running->recv_fd != -1)
+        close(data->running->recv_fd);
+    if(data->running->send_fd != -1)
+        close(data->running->send_fd);
 
-        if(data->running->recv_fd != -1)
-            close(data->running->recv_fd);
-        if(data->running->send_fd != -1)
-            close(data->running->send_fd);
-
-        ret = waitpid(data->running->pid, &status, WNOHANG);
-        if (ret == 0 && data->running->pid != 0) {
-            kill(data->running->pid, SIGKILL);
-            waitpid(data->running->pid, &status, 0);
-        }
-
-#ifdef Libisofs_extf_old_behavior_bit_0
+    ret = waitpid(data->running->pid, &status, WNOHANG);
+    if (ret == 0 && data->running->pid != 0) {
+        kill(data->running->pid, SIGKILL);
+        waitpid(data->running->pid, &status, 0);
     }
-#endif
-
     free(data->running);
     data->running = NULL;
-
-#ifdef Libisofs_extf_old_behavior_bit_0
-    if (is_0_run)
-        return 1;
-#endif
-
     return iso_stream_close(data->orig);
 }
 
@@ -324,13 +277,7 @@ int extf_stream_read(IsoStream *stream, void *buf, size_t desired)
     if (running == NULL) {
         return ISO_FILE_NOT_OPENED;
     }
-
-#ifdef Libisofs_extf_old_behavior_bit_0
-    if (running->out_eof || running->is_0_run) {
-#else
     if (running->out_eof) {
-#endif
-
         return 0;
     }
 
@@ -506,6 +453,7 @@ int extf_update_size(IsoStream *stream)
 }
 
 
+static
 IsoStream *extf_get_input_stream(IsoStream *stream, int flag)
 {
     ExternalFilterStreamData *data;
@@ -632,11 +580,7 @@ int iso_file_add_external_filter(IsoFile *file, IsoExternalFilterCommand *cmd,
     IsoStream *stream;
     off_t original_size = 0, filtered_size = 0;
 
-#ifdef Libisofs_extf_old_behavior_bit_0
-    if (cmd->behavior & (2 | 4)) {
-#else
     if (cmd->behavior & (1 | 2 | 4)) {
-#endif
         original_size = iso_file_get_size(file);
         if (original_size <= 0 ||
             ((cmd->behavior & 4) && original_size <= 2048)) {
@@ -669,3 +613,18 @@ int iso_file_add_external_filter(IsoFile *file, IsoExternalFilterCommand *cmd,
     return ISO_SUCCESS;
 }
 
+
+int iso_file_get_external_filter(IsoFile *file, IsoExternalFilterCommand **cmd,
+                                 int flag)
+{
+    IsoStream *stream;
+    ExternalFilterStreamData *data;
+
+    stream = iso_file_get_stream(file);
+    if (stream->class != &extf_stream_class)
+        return 0;
+    data = stream->data;
+    *cmd = data->cmd;
+    return 1;
+}
+
diff --git a/libisofs/libisofs.h b/libisofs/libisofs.h
index f2c347d..d928ed8 100644
--- a/libisofs/libisofs.h
+++ b/libisofs/libisofs.h
@@ -4695,6 +4695,11 @@ struct iso_external_filter_command
      */
     int refcount;
 
+    /* An optional instance id.
+     * Set to empty text if no individual name for this object is intended.
+     */
+    char *name;
+
     /* Absolute local filesystem path to the executable program. */
     char *path;
 
@@ -4709,25 +4714,25 @@ struct iso_external_filter_command
     char **argv;
 
     /* A bit field which controls behavior variations:
-
-#ifdef Libisofs_extf_old_behavior_bit_0
-     * bit0= Shortcut: 0 sized input will surely yield 0 sized output
-#else
      * bit0= Do not install filter if the input has size 0.
-#endif
-
      * bit1= Do not install filter if the output is not smaller than the input.
      * bit2= Do not install filter if the number of output blocks is
      *       not smaller than the number of input blocks. Block size is 2048.
      *       Assume that non-empty input yields non-empty output and thus do
      *       not attempt to attach a filter to files smaller than 2049 bytes.
+     * bit3= suffix was removed rather than to be added.
+     *       (Removal and adding suffixes is the task of the application.
+     *        This behavior bit serves only as reminder for the application.)
      */
     int behavior;
 
-    /* An optional instance id.
-     * Set to NULL if no individual name for this object is intended.
+    /* The eventual suffix which is supposed to be added to the IsoFile name
+     * resp. to be removed from the name.
+     * (This is to be done by the application, not by calls
+     *  iso_file_add_external_filter() or iso_file_remove_filter().
+     *  The value recorded here serves only as reminder for the application.)
      */
-    char *name;
+    char *suffix;
 };
 
 typedef struct iso_external_filter_command IsoExternalFilterCommand;
@@ -4781,6 +4786,27 @@ int iso_file_add_external_filter(IsoFile *file, IsoExternalFilterCommand *cmd,
 int iso_file_remove_filter(IsoFile *file, int flag);
 
 
+/* ts A90402 */
+/**
+ * Obtain the IsoExternalFilterCommand which is associated with the top filter
+ * stream from a data file.
+ * @param file
+ *      The data file node which shall show filtered content.
+ * @param cmd
+ *      Will return the external IsoExternalFilterCommand. This does not
+ *      increment .refcount.
+ * @param flag
+ *      Bitfield for control purposes, unused yet, submit 0.
+ * @return
+ *      1 on success, 0 if the top stream of the file is not an external filter
+ *      <0 on error
+ *
+ * @since 0.6.18
+ */
+int iso_file_get_external_filter(IsoFile *file, IsoExternalFilterCommand **cmd,
+                                 int flag);
+
+
 /* ------------------------------------------------------------------------- */
 
 #ifdef LIBISOFS_WITHOUT_LIBBURN