fop2 license - get error when using license
fop2 wont restart when using 2.28 and license - will only run in demo mode
also get unable to initialize libusb: -99 when starting

when dl'ing 2.29 - says its a 2.28 license -- whats the cost of the maintenance agreement ?
License Activation
------------------
Enter your serial code: xxxxxxxxx
Serial code available!
Registration Successfull
You must restart the FOP2 service to enable the license.
[root@voiptracker fop2]# service fop2 restart
Restarting fop2 (via systemctl): [ OK ]
[root@voiptracker fop2]# ps -ef |grep fop2
root 21758 20990 0 14:58 pts/1 00:00:00 grep --color=auto fop2

[root@voiptracker fop2]# /usr/local/fop2/fop2_server -i ens160
unable to initialize libusb: -99