This is the standard version that would be installed on the ReadyNAS if you did aapt-get install ntp-server
on the command line.
This is the current stable release right from ntp.org.
After installation the server will start immediately. However, it will take some time for the server to actually sync time and date with the official time sources. So it takes about 15 to 20 minutes until any client on your network can actually sync its time with the time source on the ReadyNAS.
Have fun with the tool and remember: Works for me, ymmv.