diff --git a/CHANGES b/CHANGES
index d5de350..ae58a3a 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,15 @@
+Version 0.9.21: 2020-01-19
+
+Michal Bursa helped improve detection of a failing USB device
+and added support for automatically starting multiple wmbusmeters
+daemons if several dongles are inserted at the same time.
+Thanks Michal!
+
+Note! The wmbusmeters.service file is replaced with wmbusmeters@.service
+and the contents of the udev file is changed. The install script
+will properly install the new files and copy the old ones to ~/old.xxxx.backup files,
+and tell the user how to reload the systemd and udev daemons.
+
 Version 0.9.20: 2019-12-11
 
 Added support for meterfilestimestamp
diff --git a/README.md b/README.md
index 76a049b..b626a63 100644
--- a/README.md
+++ b/README.md
@@ -25,7 +25,8 @@ Remove the wmbus dongle (im871a,amb8465,rfmrx2,cul,d1tc) or the generic rtlsdr d
 `make; sudo make install` will install wmbusmeters as a daemon that starts
 automatically when an appropriate wmbus usb dongle is inserted in the computer.
 (Note! make install only works for GNU/Linux. For MacOSX try to start
-`wmbusmetersd /tmp/thepidfile` from a script instead.)
+`wmbusmetersd /tmp/thepidfile` from a script instead. Here you can also override the device:
+`wmbusmetersd --device=/dev/ttyXXY --listento=t1 /tmp/thepidfile`)
 
 Check the config file /etc/wmbusmeters.conf:
 ```
@@ -93,6 +94,11 @@ Or you can start wmbusmeters with your own config files:
 wmbusmeters --useconfig=/home/me/.config/wmbusmeters
 ```
 
+You can add --device and --listento to override the settings in the config. Like this:
+```
+wmbusmeters --useconfig=/home/me/.config/wmbusmeters --device=/dev/ttyXXY --listento=t1`
+```
+
 The files/dir should then be located here:
 `/home/me/.config/wmbusmeters/etc/wmbusmeters.conf` and
 `/home/me/.config/wmbusmeters/etc/wmbusmeters.d`