Avalon 4.0 includes a small change to the authorization check done by the streaming server requiring updates to two files.  Backup your system before attempting this update.

# 1. Stop AMS
$ service ams stop

# 2. Update Avalon's AMS appliation
$ cd /opt/adobe/ams/application/avalon/
$ wget --no-check-certificate https://raw.githubusercontent.com/avalonmediasystem/avalon-vod/master/adobe/main.asc -O main.asc

# 3. Update Avalon's HLS authorization script
$ cd /usr/local/sbin/
$ wget --no-check-certificate https://raw.githubusercontent.com/avalonmediasystem/avalon-vod/master/apache/avalon_auth -O avalon_auth

# Adjust the path to AMS in the avalon_auth script if necessary
# 4. Restart AMS
$ service ams start 

# 5. Restart Apache (if not using the AMS bundled Apache)
$ service httpd restart

Test streaming to desktop and mobile devices to check that the update was successful.