diff --git a/contrib/python-wrapper.py b/contrib/python-wrapper.py
index 35897f0..5a6fe0d 100644
--- a/contrib/python-wrapper.py
+++ b/contrib/python-wrapper.py
@@ -27,8 +27,10 @@ device_names = []
 # https://github.com/raboof/nethogs/archive/v0.8.5.tar.gz
 LIBRARY_NAME = 'libnethogs.so.0.8.5'
 
-# Optionally, specify a capture filter in pcap format (same as used by
-# tcpdump(1)) or None. See `man pcap-filter` for full information.
+# EXPERIMENTAL: Optionally, specify a capture filter in pcap format (same as
+# used by tcpdump(1)) or None. See `man pcap-filter` for full information.
+# Note that this feature is EXPERIMENTAL (in libnethogs) and may be removed or
+# changed in an incompatible way in a future release.
 # example:
 # FILTER = 'port 80 or port 8080 or port 443'
 FILTER = None
diff --git a/src/libnethogs.h b/src/libnethogs.h
index af02ad5..6b2f801 100644
--- a/src/libnethogs.h
+++ b/src/libnethogs.h
@@ -53,9 +53,11 @@ typedef void (*NethogsMonitorCallback)(int action,
  * occurs.
  * @param cb A pointer to a callback function following the
  * NethogsMonitorCallback definition
- * @param filter A string (char array) pcap filter to restrict what packets
- * are captured, or NULL. The filter string format is the same as that of
- * tcpdump(1); for full details, see the man page for pcap-filter(7).
+ * @param filter EXPERIMENTAL: A string (char array) pcap filter to restrict
+ * what packets are captured, or NULL. The filter string format is the same as
+ * that of tcpdump(1); for full details, see the man page for pcap-filter(7).
+ * Note that this is EXPERIMENTAL, and may be removed or changed in a future
+ * version.
  */
 
 NETHOGS_DSO_VISIBLE int nethogsmonitor_loop(NethogsMonitorCallback cb,
@@ -69,9 +71,11 @@ NETHOGS_DSO_VISIBLE int nethogsmonitor_loop(NethogsMonitorCallback cb,
  * occurs.
  * @param cb A pointer to a callback function following the
  * NethogsMonitorCallback definition
- * @param filter A string (char array) pcap filter to restrict what packets
- * are captured, or NULL. The filter string format is the same as that of
- * tcpdump(1); for full details, see the man page for pcap-filter(7).
+ * @param filter EXPERIMENTAL: A string (char array) pcap filter to restrict
+ * what packets are captured, or NULL. The filter string format is the same as
+ * that of tcpdump(1); for full details, see the man page for pcap-filter(7).
+ * Note that this is EXPERIMENTAL, and may be removed or changed in a future
+ * version.
  * @param devc number of values in devicenames array
  * @param devicenames pointer to array of devicenames (char arrays)
  * @param all when false, loopback interface and down/not running interfaces
diff --git a/src/main.cpp b/src/main.cpp
index 0233481..729adc2 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -44,9 +44,10 @@ static void help(bool iserror) {
   output << "		-s : sort output by sent column.\n";
   output << "		-l : display command line.\n";
   output << "		-a : monitor all devices, even loopback/stopped ones.\n";
+  output << "		-f : EXPERIMENTAL: specify string pcap filter (like tcpdump)."
+            " This may be removed or changed in a future version.\n";
   output << "		device : device(s) to monitor. default is all "
             "interfaces up and running excluding loopback\n";
-  output << "		-f : specify string pcap filter (like tcpdump).\n";
   output << std::endl;
   output << "When nethogs is running, press:\n";
   output << " q: quit\n";